Constant Variable

Constant variables are those variables whose value cannot be changed during the execution of a program. Constant variable can be declared as local and global variable. Constant variable is declared with the keyword const.

Constant Variable Rule: Value of constant variable is assigned at the time of declaration only.

Syntax:
const int i = 5;
const float f = 5.5;
const char ch = 'a';
const a = 5; //can be declare as without data type.

Example 1: Constant Variable declaration.

void main()
{  
    const int a=10;
    clrscr();
    printf("Value of a = %d\n",a);
    //a=20;//error, value of constant variable cannot be changed
    getch();
}