Register Storage Class in C (Keyword)

Why do we need Register Storage Class

• Whenever we declare any variable inside C Program then memory will be randomly allocated at particular memory location.
• We have to keep track of that memory location. We need to access value of that memory location using ampersand operator i.e (&).
• If we store same variable in the register memory then we can access that memory location directly without using the Address operator.
• Register variable will be accessed faster than the normal variable thus increasing the operation and program execution.

Working & Understanding of Program

• Int number1 and number2 belongs to automatic storage class.
• So they will be stored in memory.
• Register int sum belongs to register storage class, it will be stored in register memory
• There will not be any change in calculation or working of program.
• Program will simply add the two numbers and print their sum.
• If we use sum variable in any other part of program then it will be easily accessible rather then int number1 and number2.

Example:

#include <stdio.h>
int main()
{
    int number1, number2;
    register int sum;
    printf("\nEnter the Number 1 : ");
    scanf("%d",&number1);
    printf("\nEnter the Number 2 : ");
    scanf("%d",&number2);
    sum = number1 + number2;
    printf("\nSum of Numbers : %d",sum);
    return(0);
}