01 #include<stdio.h>
02 
03 int main()
04 {
05     int i;
06     printf("Press 0 : ");
07     scanf("%d",&i);
08     if(i==0)
09     {
10         printf("Zero is PRESSED");
11     }
12     else
13     {
14         printf("Zero is NOT PRESSED");
15     }
16     return 0;
17 }

 
 OUTPUT :
 
 (1st Run)
 Press 0 : 0
 Zero is PRESSED
 
 (2nd Run)
 Press 0 : 3
 Zero is NOT PRESSED