A leap year is exactly divisible by 4 except for century years (years ending with 00). The century year is a leap year only if it is perfectly divisible by 400.

For example,

- 1999 is not a leap year
- 2000 is a leap year
- 2004 is a leap year

## Program to Check Leap Year

```
#include <stdio.h>
int main() {
int year;
printf("Enter a year: ");
scanf("%d", &year);
// leap year if perfectly divisible by 400
if (year % 400 == 0) {
printf("%d is a leap year.", year);
}
// not a leap year if divisible by 100
// but not divisible by 400
else if (year % 100 == 0) {
printf("%d is not a leap year.", year);
}
// leap year if not divisible by 100
// but divisible by 4
else if (year % 4 == 0) {
printf("%d is a leap year.", year);
}
// all other years are not leap years
else {
printf("%d is not a leap year.", year);
}
return 0;
}
```

**Output 1 **

Enter a year: 1900 1900 is not a leap year.

**Output 2 **

Enter a year: 2012 2012 is a leap year.