2. Core Programming Understand computerstorage and data types Understand computerdecision structures Identify the appropriatemethod for handlingrepetition Understand errorhandling
3. Understand computerstorage and data types Lesson Overview Students will understand computer storage and data types.In this lesson, you will learn: How a computer stores programs and instructions in computer memory Memory stacks and heaps Memory size requirements for the various data storage types Numeric data and textual data
4. Understand computerstorage and data types Review Terms Data type—a definition of a set of data that specifies the possiblerange of values of the set, the operations that can be performedon the values, and the way in which the values are stored inmemory. Garbage collection—a process for automatic recovery of heapmemory. Heap—a portion of memory reserved for a program to use for thetemporary storage of data structures whose existence or sizecannot be determined until the program is running. Memory —a device where information can be stored andretrieved. Stack—a region of reserved memory in which programs storestatus data such as procedure and function call addresses, passedparameters, and sometimes local variables.
5. Understand computerstorage and data types How a computer stores programs in memory A computer keeps data and programs in storage as follows: Primary storage—Otherwise known as random access memory(RAM), it is made of memory chips. In common usage, it refersonly to a computer’s main memory, the fast semiconductorstorage (RAM) directly connected to the processor. Secondary storage—Otherwise known as a hard drive, itconsists of a read/write head that floats above rotating platterscoated with a magnetic material.
6. Understand computerstorage and data types Memory–Stacks and Heaps Variables are stored in either a stack or heap based on their type: Value types (e.g.: int, double, float) go on the stack. Reference types (String, Object) go on the heap. * Value types in classes are stored with the instance of the class onthe heap. The stack Values in the stack are managed without garbage collectionbecause items are added and removed from the stack as last in,first out (LIFO) every time you enter or exit a scope, like a methodor statement A StackOverFlowException occurs because you have usedup all the available space in the stack.
7. Understand computerstorage and data types Memory–Stacks and Heaps (continued) The heap A heap-based memory allocation occurs when we create a newobject, at which point the compiler figures out how much memoryis needed and allocates an appropriate amount of memory spaceand returns a reference representing the memory address. A heap is used for dynamic allocation of memory. The Microsoft .NET Framework uses garbage collection to free upspace during run time. Garbage collection is an automatic process for recovery of heapmemory. Blocks of memory that had been allocated but are nolonger in use are freed, and blocks of memory still in use may bemoved to consolidate the free memory into larger blocks.
8. Understand computerstorage and data types string : text string fileName = “TheXFile.avi”; string name = “somkiet”; string message = “Warnning : Some errors occure.”;
9. Understand computerstorage and data types Data Types Numeric data types Integral types (e.g.: byte, char, int) Floating-point types (float, double) Decimal Boolean Example: bool done = false;
13. Understand computerstorage and data types Using the Numeric Data Types byte numKids = 15; char letter = ‘p’; intworldPopulation = 6692030277; float money = 201.00f; double lotsaMoney = 2.4E+12;
14. Understand computerstorage and data types Lesson Review Describe how the program statement below is stored in memory: inttennisPoints = 30; Identify the appropriate data types for each of the following values. 4233423.93 100 -2323 true
15. Assignment double num = 2; String ohSnap = "%$^&$ "; int num2 = 10.9; byte smallNum = -42; char word = 'word'; long bigNum = 12345678.9; float x = 3.5F; decimal deciNum = 4.2m;
16. Answer double num = 2; String ohSnap = "%$^&$ "; int num2 = 10.9; byte smallNum = -42; char word = 'word'; long bigNum = 12345678.9; float x = 3.5F; decimal deciNum = 4.2m;
