The document provides an introduction to data types in C++ programming language. It discusses the different levels of programming languages, common uses of C/C++, its character set, whitespace characters, and defines what a data type is. It then lists the primitive/built-in data types in C++ like integer, float, boolean, etc. and describes variables types and memory used. It also covers rules for constructing identifiers, variable declaration, and the four types of C/C++ instructions.

1. Introduction to C++
Language Datatypes
Lecture 5
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2. Levels of Programming Languages
There are 3 levels of programming
languages
i) High-Level Language
ii) Middle-Level Language
iii) Low-Level Language
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3. Uses of C/C++ Programming Language
Areas where C/C++ language can be used are
 Operating Systems
 Network Drivers
 Communication Packages
 Databases
 Language Interpreters
 Utilities
 Language Compilers
 Spreadsheets
 Text Editors
 etc etc
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4. C/C++ Character Set
C/C++ character set comprises of
following characters
 A,B,C,….Z
 a,b,c,…...z
 0,1,2,……9
 , . ; : ? ! “ / ‘ | ~
 ( ) [ ] { } < >
 + - # % _ ^ = & *
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5. White Space Characters
 The character that produces blank
space when printed is called a white
space character, e.g.
 Spaces
 Tabs
 New Lines
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6. Data Transformation
 Programs transform data from one form to another
 Input data  Output data
 Stimulus  Response
 Programming languages store and process data in
various ways depending on the type of the data;
consequently, all data read, processed, or written
by a program must have a data type
 Two distinguishing characteristics of a programming
language are the data types it supports and the
operations on those data types
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7. Data Handling
 Various types of data
 E.g. letters, numbers, symbols, etc.
 Data handling requires different data types
 Data Type: type of data that a variable
can hold and the operations that can be
performed on it.
 Logical to ask the computer to multiply a
float by an integer (1.5 x 5)
 Illogical to ask the computer to multiply a
float by a string (1.5 x FUI)

8. Constants & Variables
 Constants
 1, 56, 1.89, ’a’, ’Z’, ”BSSE”
 Variables
x = 5
y = 20
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9. What is Data Type
 A data type is a set of values, together with a set of
associated operations on those values.
 Here is the table for different types:-
Date Type Used for Examples
String
Alphanumeric
characters
“hello world”, “Islamabad”,
“Alice”
Integer Whole numbers 7, 12, 999, -47
Float (floating
point)
Number with a decimal
point
3.15, 9.06, 00.13
Character
Single alphabet or
number
‘A’, ‘9’, ‘&’ (uses ASCII)
Boolean
Representing logical
values
True, False

10. A Data Type
 A data type is
 A set of values AND
 A set of operations on those values
 A data type is used to
 Identify the type of a variable when the
variable is declared
 Identify the type of the return value of a
function
 Identify the type of a parameter expected
by a function
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11. A Data Type (continued)
 When the compiler encounters a declaration for
a variable, it sets up a memory location for it
 An operator used on a variable or variables is
legal only if
 The operator is defined in that programming
language for a variable of that type
 The variable or variables involved with the
operator are of the same or compatible
types
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12. C++ Data Types
C++ Data
Types
Primitive /
Built-in
Derived
User
Defined

13. Primitive Built-in Data Types
Type Keyword
Boolean bool
Character char
Integer int
Floating point float
Double floating point double
Valueless void
Wide character wchar_t

14. Primitive Built-in Data Types
Many of the above data types can be modify
using these modifiers:-
 signed
 unsigned
 short
 long

15. Variable Types and Memory Used
Type
Typical Size
(Byte)
Typical Range
char 1 byte -128 to 127
unsigned char 1 byte 0 to 255
signed char 1 byte -128 to 127
int 4 bytes
-2147483648 to
2147483647
unsigned int 4 bytes 0 to 4294967295
signed int 4 bytes
-2147483648 to
2147483647

16. Variable Types and Memory Used
Type
Typical Size
(Byte)
Typical Range
short int 2 bytes -32768 to 32767
unsigned short int 2 bytes 0 to 65,535
signed short int 2 bytes -32768 to 32767
long int 8 bytes
-
9,223,372,036,854,775,808
to
9,223,372,036,854,775,807
signed long int 8 bytes
-
9,223,372,036,854,775,808
to
9,223,372,036,854,775,807
unsigned long int 8 bytes
0 to
18,446,744,073,709,551,61
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17. Variable Types and Memory Used
Type
Typical Size
(Byte)
Typical Range
float 4 bytes
-3.4 x 1038 to +3.4 x 1038
(~7 digits)
double 8 bytes
-1.7 x 10308 to +1.7 x 10308
(~15 digits)
wchar_t 2 or 4 bytes 1 wide character

18. Data Types
 Boolean: for storing true or false values.
Boolean variables are declared using the
keyword bool
 String: generally means an ordered
sequence of characters, enclosing
delimiters are double quotes “some string“.
Declared using keyword string
 The sizes of variables might be different
from those shown in the above table,
depending on the compiler and the
computer you are using.
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19. Variable Declaration
When variables are declared of a
particular data type then
 the variable becomes the place where the
data is stored, and
 data types is the type of value(data) stored
by that variable.
int var;
int is the datatype of the variable,
var is the variable name
; is statement terminator

20. Identifiers
Identifiers refer to the names of
 data types, constants, variables, and
functions
 Cannot be keywords
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21. Rules for Constructing Identifiers in C++
 Can contain letters, digits and underscores,
capital letters A-Z, lowercase letters a-z,
digits 0-9, and the underscore character _
 Digit can not be the first character.
 First character must be a letter or
underscore
 Can not consist of an underscore alone.
 Usually only the first 32 characters are
significant.
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22. Rules for Constructing Identifiers in C++
(contd.)
 May not be same as keyword or function
name etc.
 There can be no embedded blanks (spaces
are not allowed).
 Keywords cannot be used as identifiers
 Identifiers are case sensitive
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23. Types of C/C++ Instructions
There are 4 types of C/C++ Instructions.
i) Type declaration Instructions
Variable types and definitions etc.
ii) Input/Output Instructions
Data Input, Data Display, Data Write
etc
iii) Control Instructions
Controls the sequence of execution of
the program instructions.
iv) Arithmetic Instructions
Arithmetic Operations etc
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