/* C program to check whether a year is leap year or not using if else statement.*/ 
#include<stdio.h>
int main()
{ 
int year;
printf("Enter a year: "); 
scanf("%d",&year); 
if(year%4 == 0) 
  { 
    if( year%100 == 0) /* Checking for a century year */ 
      { 
        if ( year%400 == 0) 
          printf("%d is a leap year.", year); 
        else 
          printf("%d is not a leap year.", year); 
      } 
   else 
     printf("%d is a leap year.", year ); 
  } 
else 
 printf("%d is not a leap year.", year);
return 0; 
}

Output 1:
Enter year: 2000 
2000 is a leap year.
Output 2:
Enter year: 1900
1900 is not a leap year.