This document discusses various data types in programming languages including primitive, string, array, record, union, and pointer types. It provides details on how each type is defined and implemented in different languages. Primitive types include integers, floats, decimals, booleans, characters. Strings can have static or dynamic lengths. Arrays can be static, dynamic and allow various index types and initialization. Records group heterogeneous data under field names. Unions allow storing different types in a variable. Pointers provide indirect addressing but require careful use to avoid dangling references.
Threads allow multiple tasks to run concurrently within a single Java program. A thread represents a separate path of execution and threads can be used to improve performance. There are two main ways to create threads: by extending the Thread class or implementing the Runnable interface. Threads transition between different states like new, runnable, running, blocked, and terminated. Synchronization is needed to prevent race conditions when multiple threads access shared resources simultaneously. Deadlocks can occur when threads wait for each other in a circular manner.
This document provides an overview of different data types in programming languages. It discusses primitive data types like integers, floating point numbers, Booleans, characters and strings. It also covers user-defined types like enumerated types, subrange types, arrays, associative arrays and records. For each type, it describes common design considerations, examples from different languages, and how they are typically implemented.
Tuples are similar to lists but are immutable. They use parentheses instead of square brackets and can contain heterogeneous data types. Tuples can be used as keys in dictionaries since they are immutable. Accessing and iterating through tuple elements is like lists but tuples do not allow adding or removing items like lists.
Functions allow programmers to organize code into reusable blocks. There are built-in functions and user-defined functions. Functions make code easier to develop, test and reuse. Variables inside functions can be local, global or nonlocal. Parameters pass data into functions, while functions can return values. Libraries contain pre-defined functions for tasks like mathematics and string manipulation.
String literals in python are surrounded by either single quotation marks, or double quotation marks. Strings can be output to screen using the print function. For example: print("hello"). Like many other popular programming languages, strings in Python are arrays of bytes representing unicode characters.
oops concept in java | object oriented programming in javaCPD INDIA
The document discusses key concepts in object-oriented programming in Java including classes, objects, inheritance, packages, interfaces, encapsulation, abstraction, and polymorphism. It provides examples to illustrate each concept. Classes define the structure and behavior of objects. Objects are instances of classes. Inheritance allows classes to extend existing classes. Packages organize related classes. Interfaces define behaviors without implementation. Encapsulation hides implementation details. Abstraction models essential features without specifics. Polymorphism allows the same method name with different signatures or overriding.
Threads allow multiple tasks to run concurrently within a single Java program. A thread represents a separate path of execution and threads can be used to improve performance. There are two main ways to create threads: by extending the Thread class or implementing the Runnable interface. Threads transition between different states like new, runnable, running, blocked, and terminated. Synchronization is needed to prevent race conditions when multiple threads access shared resources simultaneously. Deadlocks can occur when threads wait for each other in a circular manner.
This document provides an overview of different data types in programming languages. It discusses primitive data types like integers, floating point numbers, Booleans, characters and strings. It also covers user-defined types like enumerated types, subrange types, arrays, associative arrays and records. For each type, it describes common design considerations, examples from different languages, and how they are typically implemented.
Tuples are similar to lists but are immutable. They use parentheses instead of square brackets and can contain heterogeneous data types. Tuples can be used as keys in dictionaries since they are immutable. Accessing and iterating through tuple elements is like lists but tuples do not allow adding or removing items like lists.
Functions allow programmers to organize code into reusable blocks. There are built-in functions and user-defined functions. Functions make code easier to develop, test and reuse. Variables inside functions can be local, global or nonlocal. Parameters pass data into functions, while functions can return values. Libraries contain pre-defined functions for tasks like mathematics and string manipulation.
String literals in python are surrounded by either single quotation marks, or double quotation marks. Strings can be output to screen using the print function. For example: print("hello"). Like many other popular programming languages, strings in Python are arrays of bytes representing unicode characters.
oops concept in java | object oriented programming in javaCPD INDIA
The document discusses key concepts in object-oriented programming in Java including classes, objects, inheritance, packages, interfaces, encapsulation, abstraction, and polymorphism. It provides examples to illustrate each concept. Classes define the structure and behavior of objects. Objects are instances of classes. Inheritance allows classes to extend existing classes. Packages organize related classes. Interfaces define behaviors without implementation. Encapsulation hides implementation details. Abstraction models essential features without specifics. Polymorphism allows the same method name with different signatures or overriding.
This document discusses abstract data types (ADTs) and their implementation in various programming languages. It covers the key concepts of ADTs including data abstraction, encapsulation, information hiding, and defining the public interface separately from the private implementation. It provides examples of ADTs implemented using modules in Modula-2, packages in Ada, classes in C++, generics in Java and C#, and classes in Ruby. Parameterized and encapsulation constructs are also discussed as techniques for implementing and organizing ADTs.
A thread is an independent path of execution within a Java program. The Thread class in Java is used to create threads and control their behavior and execution. There are two main ways to create threads - by extending the Thread class or implementing the Runnable interface. The run() method contains the code for the thread's task and threads can be started using the start() method. Threads have different states like New, Runnable, Running, Waiting etc during their lifecycle.
Every value in Java has a data type. Java supports two kinds of data types: primitive data types and reference data types. Primitive data types represent atomic, indivisible values. Java has eight Numeric data types: byte, short, int,
An operator is a symbol that is used to perform some type of computation on its operands. Java contains a rich set of
operators. Operators are categorized as unary, binary, or ternary based on the number of operands they take. They are categorized as arithmetic, relational, logical, etc. based on the operation they perform on their operands.
long, float, double, char, and boolean. Literals of primitive data types are constants. Reference data types represent
references of objects in memory. Java is a statically typed programming language. That is, it checks the data types of all values at compile time.
PYTHON-Chapter 3-Classes and Object-oriented Programming: MAULIK BORSANIYAMaulik Borsaniya
Classes and Object-oriented Programming:
Classes: Creating a Class, The Self Variable, Constructor, Types of Variables, Namespaces, Types of Methods (Instance Methods, Class Methods, Static Methods), Passing Members of One Class to Another Class, Inner Classes
Inheritance and Polymorphism: Constructors in Inheritance, Overriding Super Class Constructors and Methods, The super() Method, Types of Inheritance, Single Inheritance, Multiple Inheritance, Method Resolution Order (MRO), Polymorphism, Duck Typing Philosophy of Python, Operator Overloading, Method Overloading, Method Overriding
Abstract Classes and Interfaces: Abstract Method and Abstract Class, Interfaces in Python, Abstract Classes vs. Interfaces,
Python supports four main numerical types - integers, long integers, floating point numbers, and complex numbers. It provides various functions for mathematical, random number, trigonometric operations and constants like pi and e. Numbers are immutable and created using literals or by assigning values. The del statement can delete single or multiple number references.
Network programming in java - PPT with Easy Programs and examples of Java InetAddress Class and java socket programming example.
Learn more @ http://java2all.com/technology/network-programming
Arrays in Python can hold multiple values and each element has a numeric index. Arrays can be one-dimensional (1D), two-dimensional (2D), or multi-dimensional. Common operations on arrays include accessing elements, adding/removing elements, concatenating arrays, slicing arrays, looping through elements, and sorting arrays. The NumPy library provides powerful capabilities to work with n-dimensional arrays and matrices.
This document discusses data abstraction and abstract data types (ADTs). It defines an ADT as a collection of data along with a set of operations on that data. An ADT specifies what operations can be performed but not how they are implemented. This allows data structures to be developed independently from solutions and hides implementation details behind the ADT's operations. The document provides examples of list ADTs and an array-based implementation of a list ADT in C++.
Algorithms Lecture 1: Introduction to AlgorithmsMohamed Loey
We will discuss the following: Algorithms, Time Complexity & Space Complexity, Algorithm vs Pseudo code, Some Algorithm Types, Programming Languages, Python, Anaconda.
Modules allow grouping of related functions and code into reusable files. Packages are groups of modules that provide related functionality. There are several ways to import modules and their contents using import and from statements. The document provides examples of creating modules and packages in Python and importing from them.
Here is a Python class with the specifications provided in the question:
class PICTURE:
def __init__(self, pno, category, location):
self.pno = pno
self.category = category
self.location = location
def FixLocation(self, new_location):
self.location = new_location
This defines a PICTURE class with three instance attributes - pno, category and location as specified in the question. It also defines a FixLocation method to assign a new location as required.
The document discusses various data structures and their classification. It begins by stating the objectives of understanding how data structures can be classified, basic data types and arrays, and problem-oriented data structures used to solve specific problems. It then defines key terms like data, information, and data structures. It describes primitive and non-primitive, linear and non-linear data structures. It also discusses basic and problem-oriented data structures like lists, stacks, queues, and trees. It provides examples and applications of different data structures.
Algorithms Lecture 2: Analysis of Algorithms IMohamed Loey
This document discusses analysis of algorithms and time complexity. It explains that analysis of algorithms determines the resources needed to execute algorithms. The time complexity of an algorithm quantifies how long it takes. There are three cases to analyze - worst case, average case, and best case. Common notations for time complexity include O(1), O(n), O(n^2), O(log n), and O(n!). The document provides examples of algorithms and determines their time complexity in different cases. It also discusses how to combine complexities of nested loops and loops in algorithms.
A Python dictionary is an unordered collection of key-value pairs where keys must be unique and immutable. It allows fast lookup of values using keys. Dictionaries can be created using curly braces and keys are used to access values using indexing or the get() method. Dictionaries are mutable and support various methods like clear(), copy(), pop(), update() etc to modify or retrieve data.
This presentation deals with pure object oriented concepts and defines basic principles of OOP's like Encapsulation , polymorphism , Inheritance and Abstraction.
A list in Python is a mutable ordered sequence of elements of any data type. Lists can be created using square brackets [] and elements are accessed via indexes that start at 0. Some key characteristics of lists are:
- They can contain elements of different types
- Elements can be modified, added, or removed
- Common list methods include append(), insert(), remove(), pop(), and sort()
The document discusses strings in C programming. It defines strings as sequences of characters stored as character arrays that are terminated with a null character. It covers string literals, declaring and initializing string variables, reading and writing strings, and common string manipulation functions like strlen(), strcpy(), strcmp(), and strcat(). These functions allow operations on strings like getting the length, copying strings, comparing strings, and concatenating strings.
This document discusses TCP/IP networking concepts in Java like sockets, datagrams, ports and protocols. It provides code examples for socket programming in Java using TCP for client-server applications and UDP for datagram transmissions. It also recommends books that cover Java networking topics in more detail.
The document discusses various primitive data types including integer, floating point, decimal, boolean, and character. It describes the evolution of character encoding from EBCDIC to ASCII to Unicode. It also covers string operations and different implementations of strings in languages. The document discusses ordinal types like enumeration and subrange. It provides details about array types including static, dynamic, and associative arrays. It compares array implementations across languages.
This document discusses abstract data types (ADTs) and their implementation in various programming languages. It covers the key concepts of ADTs including data abstraction, encapsulation, information hiding, and defining the public interface separately from the private implementation. It provides examples of ADTs implemented using modules in Modula-2, packages in Ada, classes in C++, generics in Java and C#, and classes in Ruby. Parameterized and encapsulation constructs are also discussed as techniques for implementing and organizing ADTs.
A thread is an independent path of execution within a Java program. The Thread class in Java is used to create threads and control their behavior and execution. There are two main ways to create threads - by extending the Thread class or implementing the Runnable interface. The run() method contains the code for the thread's task and threads can be started using the start() method. Threads have different states like New, Runnable, Running, Waiting etc during their lifecycle.
Every value in Java has a data type. Java supports two kinds of data types: primitive data types and reference data types. Primitive data types represent atomic, indivisible values. Java has eight Numeric data types: byte, short, int,
An operator is a symbol that is used to perform some type of computation on its operands. Java contains a rich set of
operators. Operators are categorized as unary, binary, or ternary based on the number of operands they take. They are categorized as arithmetic, relational, logical, etc. based on the operation they perform on their operands.
long, float, double, char, and boolean. Literals of primitive data types are constants. Reference data types represent
references of objects in memory. Java is a statically typed programming language. That is, it checks the data types of all values at compile time.
PYTHON-Chapter 3-Classes and Object-oriented Programming: MAULIK BORSANIYAMaulik Borsaniya
Classes and Object-oriented Programming:
Classes: Creating a Class, The Self Variable, Constructor, Types of Variables, Namespaces, Types of Methods (Instance Methods, Class Methods, Static Methods), Passing Members of One Class to Another Class, Inner Classes
Inheritance and Polymorphism: Constructors in Inheritance, Overriding Super Class Constructors and Methods, The super() Method, Types of Inheritance, Single Inheritance, Multiple Inheritance, Method Resolution Order (MRO), Polymorphism, Duck Typing Philosophy of Python, Operator Overloading, Method Overloading, Method Overriding
Abstract Classes and Interfaces: Abstract Method and Abstract Class, Interfaces in Python, Abstract Classes vs. Interfaces,
Python supports four main numerical types - integers, long integers, floating point numbers, and complex numbers. It provides various functions for mathematical, random number, trigonometric operations and constants like pi and e. Numbers are immutable and created using literals or by assigning values. The del statement can delete single or multiple number references.
Network programming in java - PPT with Easy Programs and examples of Java InetAddress Class and java socket programming example.
Learn more @ http://java2all.com/technology/network-programming
Arrays in Python can hold multiple values and each element has a numeric index. Arrays can be one-dimensional (1D), two-dimensional (2D), or multi-dimensional. Common operations on arrays include accessing elements, adding/removing elements, concatenating arrays, slicing arrays, looping through elements, and sorting arrays. The NumPy library provides powerful capabilities to work with n-dimensional arrays and matrices.
This document discusses data abstraction and abstract data types (ADTs). It defines an ADT as a collection of data along with a set of operations on that data. An ADT specifies what operations can be performed but not how they are implemented. This allows data structures to be developed independently from solutions and hides implementation details behind the ADT's operations. The document provides examples of list ADTs and an array-based implementation of a list ADT in C++.
Algorithms Lecture 1: Introduction to AlgorithmsMohamed Loey
We will discuss the following: Algorithms, Time Complexity & Space Complexity, Algorithm vs Pseudo code, Some Algorithm Types, Programming Languages, Python, Anaconda.
Modules allow grouping of related functions and code into reusable files. Packages are groups of modules that provide related functionality. There are several ways to import modules and their contents using import and from statements. The document provides examples of creating modules and packages in Python and importing from them.
Here is a Python class with the specifications provided in the question:
class PICTURE:
def __init__(self, pno, category, location):
self.pno = pno
self.category = category
self.location = location
def FixLocation(self, new_location):
self.location = new_location
This defines a PICTURE class with three instance attributes - pno, category and location as specified in the question. It also defines a FixLocation method to assign a new location as required.
The document discusses various data structures and their classification. It begins by stating the objectives of understanding how data structures can be classified, basic data types and arrays, and problem-oriented data structures used to solve specific problems. It then defines key terms like data, information, and data structures. It describes primitive and non-primitive, linear and non-linear data structures. It also discusses basic and problem-oriented data structures like lists, stacks, queues, and trees. It provides examples and applications of different data structures.
Algorithms Lecture 2: Analysis of Algorithms IMohamed Loey
This document discusses analysis of algorithms and time complexity. It explains that analysis of algorithms determines the resources needed to execute algorithms. The time complexity of an algorithm quantifies how long it takes. There are three cases to analyze - worst case, average case, and best case. Common notations for time complexity include O(1), O(n), O(n^2), O(log n), and O(n!). The document provides examples of algorithms and determines their time complexity in different cases. It also discusses how to combine complexities of nested loops and loops in algorithms.
A Python dictionary is an unordered collection of key-value pairs where keys must be unique and immutable. It allows fast lookup of values using keys. Dictionaries can be created using curly braces and keys are used to access values using indexing or the get() method. Dictionaries are mutable and support various methods like clear(), copy(), pop(), update() etc to modify or retrieve data.
This presentation deals with pure object oriented concepts and defines basic principles of OOP's like Encapsulation , polymorphism , Inheritance and Abstraction.
A list in Python is a mutable ordered sequence of elements of any data type. Lists can be created using square brackets [] and elements are accessed via indexes that start at 0. Some key characteristics of lists are:
- They can contain elements of different types
- Elements can be modified, added, or removed
- Common list methods include append(), insert(), remove(), pop(), and sort()
The document discusses strings in C programming. It defines strings as sequences of characters stored as character arrays that are terminated with a null character. It covers string literals, declaring and initializing string variables, reading and writing strings, and common string manipulation functions like strlen(), strcpy(), strcmp(), and strcat(). These functions allow operations on strings like getting the length, copying strings, comparing strings, and concatenating strings.
This document discusses TCP/IP networking concepts in Java like sockets, datagrams, ports and protocols. It provides code examples for socket programming in Java using TCP for client-server applications and UDP for datagram transmissions. It also recommends books that cover Java networking topics in more detail.
The document discusses various primitive data types including integer, floating point, decimal, boolean, and character. It describes the evolution of character encoding from EBCDIC to ASCII to Unicode. It also covers string operations and different implementations of strings in languages. The document discusses ordinal types like enumeration and subrange. It provides details about array types including static, dynamic, and associative arrays. It compares array implementations across languages.
Implementing subprograms requires saving execution context, allocating activation records, and maintaining dynamic or static chains. Activation records contain parameters, local variables, return addresses, and dynamic/static links. Nested subprograms are supported through static chains that connect activation records. Dynamic scoping searches the dynamic chain for non-local variables, while shallow access uses a central variable table. Blocks are implemented as parameterless subprograms to allocate separate activation records for block variables.
The document provides an overview of Hadoop, describing it as an open-source software framework for distributed storage and processing of large datasets across clusters of computers. It discusses key Hadoop components like HDFS for storage, MapReduce for distributed processing, and YARN for resource management. The document also gives examples of how organizations are using Hadoop at large scale for applications like search indexing and data analytics.
How to build a news website use CMS wordpressbaran19901990
This tutorial wil show you, how to build a news website use CMS Wordpress step by step. From basic to advantage. I think that this tutorial is amazing and very basic for newbie.
HBase is a distributed, column-oriented database that runs on top of Hadoop and HDFS, providing Bigtable-like capabilities for massive tables of structured and unstructured data. It is modeled after Google's Bigtable and provides a distributed, scalable, versioned storage system with strong consistency for random read/write access to billions of rows and millions of columns. HBase is well-suited for handling large datasets and providing real-time read/write access across clusters of commodity servers.
This document discusses subprograms (also called subroutines) in programming languages. It covers:
- The basic definitions and characteristics of subprograms, including headers, parameters, and local variables.
- Different parameter passing methods like pass-by-value, pass-by-reference, and their implementation in common languages.
- Additional features of subprograms including overloading, generics, and functions passing subprograms as parameters.
1) The document discusses water passing through a pressure-reducing valve and separating tank, including its state and amount that leaves as vapor.
2) It also discusses heat transfer calculations for air heated in an exchanger and flow rate measurement using a venturi meter.
3) Heat transfer principles and equations are reviewed for various processes, including perfect gas behavior, convection coefficients, radiation from a human body, and insensible evaporation heat loss.
The document discusses configuring websocket on Apache by installing Apache on CentOS, installing the websocket_rails gem and Redis, configuring a virtual host with a proxy server, and starting the websocket_rails server. Key steps include installing Apache, installing websocket_rails and Redis, configuring a virtual host to proxy websocket requests to the websocket_rails server on port 3001, and initializing websockets in JavaScript by connecting to the server hostname and port.
The document discusses syntax analysis and parsing. It covers context-free grammars, Backus-Naur Form (BNF), Extended BNF, and different parsing techniques like recursive descent parsing and LL parsing. It also discusses Scala's combinator parser, which uses parser combinators to parse input based on a grammar.
Three types of memory allocation are used: fixed memory for static data, stack memory for function calls and local variables, and heap memory for dynamic data. Stack memory uses activation records to store function arguments, return addresses and local variables. Heap memory requires memory management through techniques like free lists, allocation algorithms, and garbage collection to allocate and free dynamic structures. Garbage collection identifies inaccessible data using reference counting or mark and sweep to free memory.
This document contains review questions from chapters 9 and 10 of the textbook "Theory of Programming Languages". Chapter 9 discusses subprograms including formal/actual parameters, parameter passing methods, and overloading. Chapter 10 covers implementation of subprograms including activation records, static/dynamic scoping, and nonlocal variable access using static chains and displays. In summary, the document reviews key concepts about subprogram definition, execution, and implementation in programming languages.
This document discusses scope in programming languages. Scope refers to the context where a variable name is valid and can be used. There are two types of scope: static and dynamic. With static scope, a variable's scope is the block of code it is defined in such as a function. With dynamic scope, a variable's scope is the period of time a function executes, so the variable remains accessible after the function returns. The key difference is that static scope searches parent blocks for variable names while dynamic scope searches called functions.
The document discusses computer languages and programming. It describes three categories of programming languages: machine languages, assembly languages, and high-level languages. It also discusses common programming language tools like assemblers, compilers, linkers, and interpreters. Popular programming languages like FORTRAN, COBOL, BASIC, Pascal, C, C++, C#, Java, RPG, LISP and SNOBOL are also mentioned. The key characteristics and uses of machine languages, assembly languages, high-level languages, compilers, linkers and interpreters are summarized.
This document provides an overview of logic programming and the logic programming language Prolog. It discusses key concepts in logic programming like predicates, clauses, resolution, and backward chaining. It also describes the basic syntax and execution model of Prolog, including how it uses unification, backtracking, and trace to evaluate queries against a knowledge base of facts and rules.
This document discusses abstract data types and encapsulation. It explains that abstract data types define a set of objects, operations on those objects, and encapsulate them so the user cannot directly access the hidden data. Encapsulation through subprograms and type definitions is described. Different approaches to static and dynamic storage management like stacks, heaps, and garbage collection are also summarized.
This document discusses different data types in C/C++ including character, integer, and real (float) data types. It explains that character data can be signed or unsigned and occupies 1 byte, integer data represents whole numbers using the int type, and float data represents decimal numbers. The document also covers numeric and non-numeric constants in C/C++ such as integer, octal, hexadecimal, floating point, character, and string constants.
This document discusses data types, expressions, and assignment statements in programming languages. It covers:
- Primitive data types like integers, floats, Booleans provided by most languages. Character strings can be primitive or arrays.
- User-defined types like enumerations and subranges. Array types can be static, dynamic, or have different index types. Unions and pointers/references are also covered.
- Expressions involve operators, operands, and evaluation order. Operator overloading and type conversions are design considerations.
- Assignment statements use operators like = and := to change variable values. Compound and unary operators provide shorthand. Assignment can produce results used as expressions in some languages.
This document discusses different data types in programming languages. It covers primitive data types like integers, floats, decimals, booleans and characters. It also discusses string types, user-defined types like enumerations and subranges, and array types. For each type it describes common implementations in languages and considerations in their design.
The document discusses various primitive data types including integer, floating point, decimal, boolean, character, and string types. It covers the implementation and design considerations of these types in different programming languages such as C, C++, Java, and C#. Enumeration types are also introduced as user-defined ordinal types.
This document discusses different data types in programming languages. It begins by introducing primitive data types like integers, floating point numbers, decimals, Booleans, and characters. It then covers string types, describing how they are implemented in different languages like C, Java, and SNOBOL4. The document also discusses user-defined types and structured types like arrays and records. It provides details on key topics related to data types, including type operators, descriptors, objects, and design issues around operations and representation.
The document discusses different data types in programming languages including primitive, character string, enumeration, array, and other types. It provides details on each type, such as what they are, common operations, and design considerations. Array types are discussed in depth, covering topics like indexing, binding, initialization, dimensionality, and whether elements must be of the same type. Implementation details are also presented for different data types.
This document discusses different data types used in programming languages. It covers primitive data types implemented directly in hardware like integers and floating point numbers. It also discusses common composite types like strings, arrays, records, and enumerations. The document examines how various programming languages have implemented and extended these basic types over time to provide more powerful abstractions.
This document discusses different data types used in programming languages. It covers primitive data types implemented directly in hardware like integers and floating point numbers. It also discusses common composite types like strings, arrays, records, and enumerations. The document examines how various programming languages have implemented and extended these basic types over time to provide more powerful abstractions.
This document discusses various data types in programming languages. It begins by introducing fundamental concepts like data types, descriptors, and objects. It then covers primitive data types like integers, floats, characters, and more. It also discusses user-defined types like enumerated types, subrange types, arrays, records, tuples, lists, and unions. For each type, it discusses design considerations and implementation details. It provides examples from many popular languages to illustrate how different languages approach each data type.
This document discusses different data types in programming languages including numeric, Boolean, character, user-defined, and array data types. It describes the key characteristics of integer, floating-point, decimal, complex, Boolean, string, enumeration, static array, stack-dynamic array, fixed heap-dynamic array, and heap-dynamic array data types. The document aims to explain how different languages handle various data types and the pros and cons of each approach.
This document discusses different data types, including primitive data types, strings, enumerated types, subrange types, and arrays. It describes the characteristics and design considerations of each type, provides examples in various programming languages, and discusses how each type is typically implemented. The key topics covered include the common primitive types like integer and floating point, static versus dynamic string lengths, enumeration syntax and usage, subrange constraints, array indexing and dimensions, and static versus dynamic array allocation.
The .NET Framework is a development tool that supports building applications and XML web services. It supports 61 programming languages, including 9 designed by Microsoft. Code in .NET is compiled twice - first to MSIL then to native code using the CLR. The Framework Class Library is a huge reusable library of types for managed code, providing access to system functions. Namespaces organize types and provide context. Common namespaces include System, System.Data, and System.Collections. Keywords have special meanings and identifiers name variables, methods, etc. Arrays come in various types like normal, huge, static, dynamic, and jagged. The Array class provides methods like sort, clear, and copy.
Apache Avro is a data serialization system that is compact, fast, and provides support for RPC mechanisms and data evolution. It uses JSON schemas and efficient binary encoding. Avro is built for large datasets and supports features like schema validation, dynamic typing, sorting, and protocol definitions for language-independent RPCs.
This document provides an introduction to Python, including:
- Python is an open source, high-level programming language that is dynamic typed and includes many standard modules.
- It can be used for GIS tasks like interfacing with ArcGIS and automating geoprocessing workflows.
- Key Python concepts covered include strings, lists, tuples, dictionaries, conditionals, loops, modules, and error handling.
- The document demonstrates how to use the Python IDLE development environment and provides additional resources for learning Python.
This document provides an introduction to Python, including:
- Python is an open source, high-level programming language that is dynamic typed and includes many standard modules.
- It can be used for GIS tasks like interfacing with ArcGIS and automating geoprocessing workflows.
- Key Python concepts covered include strings, lists, tuples, dictionaries, conditionals, loops, modules, and error handling.
- The document demonstrates how to use the Python interactive shell and development environments like IDLE.
The document outlines an agenda for learning core Java concepts over 15 sections. It introduces key Java topics like primitive data types, variables, arrays, control flow statements, classes and objects, inheritance, polymorphism, exceptions, strings and characters, files and streams, and generic collections. The agenda also covers defining classes and methods, passing arguments, encapsulation, and memory concepts like objects, references, and the heap.
The document discusses various data types in programming languages including primitive, user-defined, arrays, strings, records, unions, pointers, and sets. It covers the evolution of data types from early languages like FORTRAN to modern languages like Ada and Java. Key design issues are identified for each data type regarding syntax, operations, static vs dynamic binding, and type checking. Examples are provided for how different languages implement each data type. Problems with certain data types like pointers are also discussed regarding dangling pointers and lost heap variables.
This document discusses different data types including primitive data types like integers, floating-point numbers, characters, and Booleans. It describes numeric types like integers that have subtypes like byte, short, int, and long. Floating-point types are described as having precision and range. Character types store characters using encodings like ASCII and Unicode. String types can have static, limited dynamic, or dynamic lengths. Other topics covered include enumeration types that define named constants, subrange types that define subsets of other types, and array types that group homogeneous elements.
This document provides information on variables, data types, and keywords in C# programming. It discusses the differences between static and normal variables, with static variables allocating memory in the class and maintaining their value until the application closes. Different data types are described like integral, floating point, and nullable types. Value, reference, and pointer data types are also explained. The document contains code examples demonstrating static and normal variables as well as printing the limits of different data types. Keywords in C# that cannot be used as identifiers are listed.
The document provides an overview of the basics of Java programming. It covers the evolution of programming languages, popular languages in 2018, the history of Java, Java modules like J2SE, J2EE and J2ME. It also discusses why Java is chosen, applications of Java, and key concepts like JDK, JRE, JVM. The document then explains how to create Java code, variables and data types, arrays, Strings, and the Object class in Java.
Scala is a programming language that combines object-oriented and functional programming. It runs on the Java Virtual Machine and is designed to grow with user demands through libraries. Play 2.0 is a web application framework written in Scala that allows for rapid development through its Model-View-Controller architecture and local development server. Cloud Foundry is an open Platform as a Service that allows developers to easily deploy and scale applications, including those written in Scala and Play 2.0.
This document discusses key concepts related to variables in programming languages including names, bindings, scopes, and lifetimes. It covers different types of variables such as static, stack dynamic, and heap dynamic variables. It also compares static and dynamic scoping models and how they determine variable visibility. The referencing environment is defined as the collection of all visible variables for a given statement.
The document discusses lexical analysis, which is the first stage of syntax analysis for programming languages. It covers terminology, using finite automata and regular expressions to describe tokens, and how lexical analyzers work. Lexical analyzers extract lexemes from source code and return tokens to the parser. They are often implemented using finite state machines generated from regular grammar descriptions of the lexical patterns in a language.
The document provides information about a programming languages course, including:
- The lecturer's details and contact information.
- Assessment criteria including tutorials, assignments, exams.
- An outline of course topics such as language categories, evaluation criteria, and implementation methods.
- References and resources used in the course.
This document discusses principles of sequence control in programming languages. It covers expressions, assignment statements, selection statements like if/else and switch/case, and iterative statements like for, while, and loops controlled by data structures. It provides examples of how these concepts are implemented in different languages like C, Pascal, and C#. Unconditional branching with goto is also discussed, noting that while powerful it can hurt readability so most modern languages avoid or restrict it.
To install git on Ubuntu, the document outlines 6 steps: 1) create a GitHub account using your company email, 2) read documentation on using git, 3) install git via terminal commands, 4) configure git with your name and email, 5) verify settings, and 6) review common git commands like cloning, adding, committing, and pushing files. The summary is to create a GitHub account, get added to your company's GitHub by sending your profile URL to your leader.
Ruby has methods to convert objects to different data types: to_s converts objects to strings, to_i converts objects to integers, and to_a converts objects to arrays. Arrays in Ruby are denoted using square brackets [].
Controllers handle web requests from users and interact with views and models. Views display templates filled with application data and convert it to HTML. Models represent and wrap application data stored in the database. Helpers assist models, views, and controllers. Common Rails methods include link_to for creating links and migrations for modifying the database schema by adding, removing, or changing columns.
This document provides instructions for various commands in Vim and Git. In Vim, I inserts text while in Normal mode commands like :wq save and quit. dd deletes the current line while yy copies it. Git commands like git add stage changes and git commit commits them to the local repository. git push pushes local changes to the remote server repository.
The document discusses metamodeling and its use in the MDA framework. It defines key terms like model, language, metamodel, and metalanguage. A metamodel is a model that defines the constructs and rules of a modeling language. It allows unambiguous definition of languages so transformation tools can process models. Transformation rules in a definition reference the source and target metamodels to specify how one model transforms to another. Metamodeling provides the mechanism to formally define modeling languages in MDA.
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HijackLoader Evolution: Interactive Process HollowingDonato Onofri
CrowdStrike researchers have identified a HijackLoader (aka IDAT Loader) sample that employs sophisticated evasion techniques to enhance the complexity of the threat. HijackLoader, an increasingly popular tool among adversaries for deploying additional payloads and tooling, continues to evolve as its developers experiment and enhance its capabilities.
In their analysis of a recent HijackLoader sample, CrowdStrike researchers discovered new techniques designed to increase the defense evasion capabilities of the loader. The malware developer used a standard process hollowing technique coupled with an additional trigger that was activated by the parent process writing to a pipe. This new approach, called "Interactive Process Hollowing", has the potential to make defense evasion stealthier.
3. Introduction
•A data type defines
–a collection of data objects
–a set of predefined operations
•Abstract Data Type: Interface (visible) are separated from the representation and operation (hidden)
•Uses of type system:
–Error detection
–Program modularization assistant
–Documentation
4. The Next Part
•Primitive Data Types
•Character String Types
•User-Defined Ordinal Types
•Array Types
•Associative Arrays
•Record Types
•Union Types
•Pointer and Reference Types
•Type Checking
5. Primitive Data Types
•Data types that are not defined in terms of other data types
•Some primitive data types are merely reflections of the hardware
•Others require little non-hardware support
6. Primitive Data Types: Integer
•Languages may support several sizes of integer
–Java’s signed integer sizes: byte, short, int, long
•Some languages include unsigned integers
•Supported directly by hardware: a string of bits
•To represent negative numbers: twos complement
7. Primitive Data Types: Floating Point
•Model real numbers, but only as approximations
•Languages for scientific use support at least two floating-point types (e.g., float and double)
•Precision and range
•IEEE Floating-Point Standard 754
9. Primitive Data Types: Decimal
•For business applications (money)
–Essential to COBOL
–C# offers a decimal data type
•Store a fixed number of decimal digits
•Advantage: accuracy
•Disadvantages: limited range, wastes memory
10. Primitive Data Types: Boolean
•Simplest of all
•Range of values: two elements, one for “true” and one for “false”
•Could be implemented as bits, but often as bytes
–Advantage: readability
11. Primitive Data Types: Character
•Stored as numeric codings
•Most commonly used coding: ASCII
•An alternative, 16-bit coding: Unicode
–Includes characters from most natural languages
–Originally used in Java
–C# and JavaScript also support Unicode
12. Character String Types
•Values are sequences of characters
•Design issues:
–Is it a primitive type or just a special kind of array?
–Should the length of strings be static or dynamic?
14. •C and C++
–Not primitive
–Use char arrays and a library of functions that provide operations
•Java
–Primitive via the String class
–Immutable
Character String in Some Languages
15. Character String Length Options
•Static: Python, Java’s String class
•Limited Dynamic Length: C
–In C, a special character is used to indicate the end of a string’s characters, rather than maintaining the length
•Dynamic (no maximum): Perl, JavaScript, standard C++ library
•Ada supports all three string length options
16. Character String Type Evaluation
•Aid to writability
•As a primitive type with static length, they are inexpensive to provide--why not have them?
•Dynamic length is nice, but is it worth the expense?
17. Character String Implementation
•Static length: compile-time descriptor
•Limited dynamic length: may need a run-time descriptor for length (but not in C and C++)
•Dynamic length: need run-time descriptor; allocation/de-allocation is the biggest implementation problem
19. User-Defined Ordinal Types
•An ordinal type is one in which the range of possible values can be easily associated with the set of positive integers
•Examples of primitive ordinal types in Java
–integer
–char
–boolean
20. Enumeration Types
•All possible values, which are named constants, are provided in the definition
•C# example
enum days {Mon, Tue, Wed, Thu, Fri, Sat, Sun};
days myDay = Mon, yourDay = Tue;
•Design issues:
–Is an enumeration constant allowed to appear in more than one type definition?
–Are enumeration values coerced to integer?
–Are any other types coerced to an enumeration type?
21. Evaluation of Enumerated Type
•Readability
–no need to code a color as a number
•Reliability
–Ada, C# and Java 5.0
•operations (don’t allow colors to be added)
•No enumeration variable can be assigned a value outside its defined range
•Better support for enumeration than C++: enumeration type variables are not coerced into integer types
22. •Enumeration types are implemented as integers
Implementation of User-Defined Ordinal Types
23. The Next Part
•Primitive Data Types
•Character String Types
•User-Defined Ordinal Types
•Array Types
•Associative Arrays
•Record Types
•Union Types
•Pointer and Reference Types
•Type Checking
24. Array Types
•Collection of homogeneous data elements
•Each element is identified by its position relative to the first element
•Homogeneous: data elements are of same type
•Referenced using subscript expression
25. Array Indexing
•Indexing (or subscripting) is a mapping from indices to elements
array_name (index_value_list) an element
•Index Syntax
–Fortran, Ada use parentheses
–Most other languages use brackets
26. Arrays Index (Subscript) Types
•What type are legal for subscripts?
•Pascal, Ada: any ordinal type (integer, boolean, char, enumeration)
•Others: subrange of integers
•Are subscripting expressions range checked?
•Most contemporary languages do not specify range checking but Java, ML, C#
•Unusual case: Perl
27. •Static: subscript ranges are statically bound and storage allocation is static
–Advantage: efficiency (no dynamic allocation)
–Disadvantage: storage is bound all the time
•Fixed stack-dynamic: subscript ranges are statically bound, but the allocation is done at declaration time
–Advantage: space efficiency
–Disadvantage: dynamic allocation
Subscript Binding & Array Categories
28. •Stack-dynamic: subscript ranges are dynamically bound and the storage allocation is dynamic (done at run-time)
–Advantage: flexibility (the size of an array need not be known until the array is to be used)
•Fixed heap-dynamic: similar to fixed stack- dynamic: storage binding is dynamic but fixed after allocation (i.e., binding is done when requested and storage is allocated from heap, not stack)
Subscript Binding & Array Categories
29. •Heap-dynamic: binding of subscript ranges and storage allocation is dynamic and can change any number of times
–Advantage: flexibility (arrays can grow or shrink during program execution)
Subscript Binding & Array Categories
30. Subscript Binding & Array Categories
•C and C++ arrays that include static modifier are static
•C and C++ arrays without static modifier are fixed stack-dynamic
•Ada arrays can be stack-dynamic
Get(List_Len);
declare
List : array (1..List_Len) of Integer;
begin
...
end;
31. Subscript Binding & Array Categories
•C and C++ provide fixed heap-dynamic arrays
–malloc and free, new and delete
•All arrays in Java are fixed heap-dynamic
•C# includes a array class ArrayList that provides heap-dynamic
ArrayList intList = new ArrayList();
intList.Add(nextOne);
•Perl and JavaScript support heap-dynamic arrays
32. Array Initialization
•Some language allow initialization at the time of storage allocation
–C, C++, Java, C# example
int list [] = {4, 5, 7, 83}
–Character strings in C and C++
char name [] = "freddie";
–Arrays of strings in C and C++
char *names [] = {"Bob", "Jake", "Joe"];
–Java initialization of String objects
String[] names = {"Bob", "Jake", "Joe"};
33. Arrays Operations
•Assignment, catenation, comparison for equality, and slices
•C-based languages do not provide any array operations
•Java, C++ and C# use methods to manipulate
35. Slices
•A slice is some substructure of an array; nothing more than a referencing mechanism
•Slices are only useful in languages that have array operations
•E.g. Python
vector = [2, 4, 6, 8, 10, 12, 14, 16]
mat = [[1, 2, 3],[4, 5, 6],[7, 8, 9]]
vector[3:6], mat[1], mat[0][0:2]
36. Implementation of Arrays
•Access function maps subscript expressions to an address in the array
•Single-dimensioned: list of adjacent memory cells
•Access function for single-dimensioned arrays:
address(list[k]) = address (list[lower_bound])
+ ((k-lower_bound) * element_size)
37. Accessing Multi-dimensioned Arrays a[ 0, 0 ]
a[ 0, 1 ]
a[ 0, 2 ]
a[ 1, 0 ]
a[ 1, 1 ]
a[ 1, 2 ] a[ 0, 0 ]
a[ 1, 0 ]
a[ 0, 1 ]
a[ 1, 1 ]
a[ 0, 2 ]
a[ 1, 2 ]
Row major order – used in most languages
Column major order – used in Fortran
38. • General format Location (a[I,j]) = address of a [row_lb,col_lb] + (((I - row_lb) * n) + (j - col_lb)) * element_size
Accessing Multi-dimensioned Arrays
40. Associative Arrays
•An associative array is an unordered collection of data elements that are indexed by an equal number of values called keys
–User defined keys must be stored
•Similar to Map in Scala
•Design issues: What is the form of references to elements
41. Associative Arrays in Perl
•Names begin with %; literals are delimited by parentheses
%hi_temps = ("Mon" => 77, "Tue" => 79, “Wed” => 65, …);
•Subscripting is done using braces and keys
$hi_temps{"Wed"} = 83;
–Elements can be removed with delete
delete $hi_temps{"Tue"};
42. Record Types
•A record:
–heterogeneous aggregate of data elements
–individual elements are identified by names
•Popular in most languages, OO languages use objects as records
•Design issues:
–What is the syntactic form of references to the field?
–Are elliptical references allowed
43. Definition of Records in Ada
•Record structures are indicated in an orthogonal way
type Emp_Name_Type is record
First: String (1..20);
Mid: String (1..10);
Last: String (1..20);
end record;
type Emp_Record_Type is record
Emp_Name: Emp_Name_Type;
Hourly_Rate: Float;
end record;
Emp_Rec: Emp_Rec_Type;
44. References to Records
•Most language use dot notation
Emp_Rec.Emp_Name.Mid
•Fully qualified references must include all record names
•Elliptical references allow leaving out record names as long as the reference is unambiguous, for example in COBOL
FIRST, FIRST OF EMP-NAME, and FIRST OF EMP-REC are elliptical references to the employee’s first name
45. Operations on Records
•Assignment is very common if the types are identical
•Ada allows record comparison
•Ada records can be initialized with aggregate literals
•COBOL provides MOVE CORRESPONDING
–Copies fields which have the same name
46. •Straight forward and safe design
•Arrays are used when all data values have the same type and/or are processed in the same way
•Records are opposite
•Arrays: dynamic subscripting
•Records: static subscripting
Evaluation
47. Offset address relative to the beginning of the records is associated with each field
Implementation of Record Type
48. Unions Types
•A union is a type whose variables are allowed to store different type values at different times during execution
•Design issues
–Should type checking be required?
–Should unions be embedded in records?
49. Discriminated vs. Free Unions
•Fortran, C, and C++ provide union constructs in which there is no language support for type checking; the union in these languages is called free union
•Type checking of unions require that each union include a type indicator called a discriminant
–Supported by Ada
50. Ada Union Types
type Shape is (Circle, Triangle, Rectangle);
type Colors is (Red, Green, Blue);
type Figure (Form: Shape) is record
Filled: Boolean;
Color: Colors;
case Form is
when Circle => Diameter: Float;
when Triangle =>
Leftside, Rightside: Integer;
Angle: Float;
when Rectangle => Side1, Side2: Integer;
end case;
end record;
51. Ada Union Type Illustrated
A discriminated union of three shape variables
52. Evaluation of Unions
•Potentially unsafe construct
–Do not allow type checking
•Java and C# do not support unions
–Reflective of growing concerns for safety in programming language
53. Pointer and Reference Types
•A pointer type variable has a range of values that consists of memory addresses and a special value, nil
•Provide the power of indirect addressing
•Provide a way to manage dynamic memory
•A pointer can be used to access a location in the area where storage is dynamically created (usually called a heap)
54. Design Issues of Pointers
•What are the scope of and lifetime of a pointer variable?
•What is the lifetime of a heap-dynamic variable?
•Are pointers restricted as to the type of value to which they can point?
•Are pointers used for dynamic storage management, indirect addressing, or both?
•Should the language support pointer types, reference types, or both?
55. Pointer Operations
•Two fundamental operations: assignment and dereferencing
•Assignment is used to set a pointer variable’s value to some useful address
•Dereferencing yields the value stored at the location represented by the pointer’s value
–Dereferencing can be explicit or implicit
–C++ uses an explicit operation via *
j = *ptr
sets j to the value located at ptr
57. Pointer Operations
•Pointer points to a record in C/C++
–Explicit: (*p).name
–Implicit: p -> name
•Management of heap use explicit allocation
–C: subprogram malloc
–C++: new and delete operators
58. Problems with Pointers
•Dangling pointers (dangerous)
–A pointer points to a heap-dynamic variable that has been de-allocated
•Lost heap-dynamic variable
–An allocated heap-dynamic variable that is no longer accessible to the user program (often called garbage)
59. Pointers in Ada
•access types
•Some dangling pointers are disallowed because dynamic objects can be automatically de-allocated at the end of pointer's type scope
•The lost heap-dynamic variable problem is not eliminated by Ada
60. Pointers in C and C++
int *ptr;
int count, init;
...
ptr = &init;
count = *ptr;
•Extremely flexible but must be used with care
•Pointers can point at any variable regardless of when it was allocated
•Used for dynamic storage management and addressing
61. Pointers in C and C++
•Pointer arithmetic is possible
int list [10]; int *ptr; ptr = list;
*(ptr + 1)
*(ptr + index)
*ptr[index]
•Explicit dereferencing and address-of operators
•Domain type need not be fixed (void *)
•void * can point to any type and can be type checked (cannot be de-referenced)
62. •C++ includes a special kind of pointer type called a reference type that is used primarily for formal parameters
•Java extends C++’s reference variables and allows them to replace pointers entirely
–References refer to call instances
•C# includes both the references of Java and the pointers of C++
Reference Types
63. Evaluation of Pointers
•Dangling pointers and dangling objects are problems as is heap management
•Pointers are like goto's--they widen the range of cells that can be accessed by a variable
•Essential in some kinds of programming applications, e.g. device drivers
•Using references provide some of the flexibility and capabilities of pointers, without the hazards
64. Representations of Pointers
•Large computers use single values
•Intel microprocessors use segment and offset
65. Dangling Pointer Problem
•Tombstone: extra heap cell that is a pointer to the heap-dynamic variable
–The actual pointer variable points only at tombstones
–When heap-dynamic variable de-allocated, tombstone remains but set to nil
–Costly in time and space
•Locks-and-keys: Pointer values are represented as (key, address) pairs
–Heap-dynamic variables are represented as variable plus cell for integer lock value
–When heap-dynamic variable allocated, lock value is created and placed in lock cell and key cell of pointer
66. Type Checking
•Generalize the concept of operands and operators to include subprograms and assignments
•Type checking is the activity of ensuring that the operands of an operator are of compatible types
•A compatible type is one that is either legal for the operator, or is allowed under language rules to be implicitly converted by compiler- generated code to a legal type
–This automatic conversion is called a coercion.
•A type error is the application of an operator to an operand of an inappropriate type
67. Type Checking (continued)
•If all type bindings are static, nearly all type checking can be static
•If type bindings are dynamic, type checking must be dynamic
•A programming language is strongly typed if type errors are always detected
68. Strong Typing
•Advantage of strong typing: allows the detection of the misuses of variables that result in type errors
•Language examples:
–FORTRAN 77 is not: EQUIVALENCE
–C and C++ are not: unions are not type checked
–Java, C#: strongly typed
69. Strong Typing (continued)
•Coercion rules strongly affect strong typing-- they can weaken it considerably (C++ versus Ada)
•Although Java has just half the assignment coercions of C++, its strong typing is still far less effective than that of Ada
70. Name Type Equivalence
•Name type equivalence means the two variables have compatible types if they are in either the same declaration or in declarations that use the same type name
•Easy to implement but highly restrictive:
–Subranges of integer types are not compatible with integer types
–Formal parameters must be the same type as their corresponding actual parameters (Pascal)
71. Structure Type Equivalence
•Structure type equivalence means that two variables have equivalent types if their types have identical structures
•More flexible, but harder to implement
72. Structure Type Equivalence
•Consider the problem of two structured types:
–Are two record types equivalent if they are structurally the same but use different field names?
–Are two array types equivalent if they are the same except that the subscripts are different?
(e.g. [1..10] and [0..9])
–Are two enumeration types equivalent if their components are spelled differently?
–With structural type equivalence, you cannot differentiate between types of the same structure (e.g. different units of speed, both float)
73. Summary
•The data types of a language are a large part of what determines that language’s style and usefulness
•The primitive data types of most imperative languages include numeric, character, and Boolean types
•The user-defined enumeration and subrange types are convenient and add to the readability and reliability of programs
•Arrays and records are included in most languages
•Pointers are used for addressing flexibility and to control dynamic storage management
•Strong typing means detecting all type errors