Variable:

Variable is an entity whose value can vary (i.e. change) during execution of a program.

int a = 20;

int a

  1. #include<stdio.h>
  2. main()
  3. {
  4. printf("********* Example Variable *********\n");
  5. int i, j;
  6. i = 10; j = 20;
  7. printf("\n value of i=%d & j=%d \n",i, j);
  8. // change the value of variable
  9. printf("\n change value of variable ");
  10. i = 50;
  11. printf("\n After changing value of variable i is : %d \t", i);
  12. getch();
  13. }
main

Real life example of variable

Constant:

Constant is an entity whose value cannot be changed throughout the execution of program.

const int j = 50;
constant

  1. #include<stdio.h>
  2. main()
  3. {
  4. printf("********* Example Constant *********\n");
  5. const int i = 100;
  6. printf("\n value of constant i= %d \n",i);
  7. i = 50;
  8. printf("\n%d \t", i);
  9. getch();
  10. }
Output: Will give an error because we cannot change the value of constant variable.
  1. #include<stdio.h>
  2. main()
  3. {
  4. printf("********* Example Constant *********\n");
  5. const int i ;
  6. printf("\n value of constant i= %d \n",i);
  7. //i = 50;
  8. printf("\n%d \t", i);
  9. getch();
  10. }
output

Real life example of constant

Summary:

This article will help fresher candidates to understand Variables & Constants in C with Real Life Example.