C++ Variables reserved memory location or space of memory for store value .Integer is a whole number and Interger written as in c++ is int. Type and identify are two type variable define. for example int myVariable = 5 ; Finally we can say data type name for variable is int.
There are following basic types of variable in C++ as explained in last chapter
|Sr.No||Type & Description|
Stores either value true or false.
Typically a single octet (one byte). This is an integer type.
The most natural size of integer for the machine.
A single-precision floating point value.
A double-precision floating point value.
Represents the absence of type.
A wide character type.
Declaration and Initialization
Variable must be declared before they are used. Usually it is preferred to declare them at the starting of the program, but in C++ they can be declared in the middle of program too, but must be done before using them.
int i; // declared but not initialised char c; int i, j, k; // Multiple declaration
Initialization means assigning value to an already declared variable,
int i; // declaration i = 10; // initialization
Initialization and declaration can be done in one single step also,
int i=10; //initialization and declaration in same step int i=10, j=11;
If a variable is declared and not initialized by default it will hold a garbage value. Also, if a variable is once declared and if try to declare it again, we will get a compile time error.
int i,j; i=10; j=20; int j=i+j; //compile time error, cannot redeclare a variable in same scope