# 46 : C Program to Check Entered Number is a Leap Year or not

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What is a leap year ?

Earth takes 365.242199 days to complete its orbit around the sun. So we have leap years. A Leap year has 366 days (i.e febuary with 29 days as 1 day is added every 4th year) is called as a leap year. This happens every 4th year.

Note : To get to more closer to 365.242199 days/year, every 100th year is not a leap year!! Where as every 400th year is a leap year!

Logic to find leap year in C

Every 4th year is a leap year. And number divisible by 400 is a leap year, But number divisible by 100 is not a leap year! This can be achieved using if condition and modulo division with conditions like,

``````
if ((year % 400 == 0) || ( ( year % 100 != 0) && (year % 4 == 0 ))) {

//Leap year!
}
else {

//Not a leap year!
}
```
```

Variables :

year : Datatype int : Holds value of year inputted by the user. %d is the Format specifier for int's

``````
/*
* 1000+ C programs + tutorials
*
*
* 41_Check_entered_year_is_a_leapyear.c
*
*
*  Created on: Oct 20, 2014
*  Author: Code2care.org
*/

#include
//#include

void main() {

int year;

//clrscr();

printf("C Program to Find Entered Year is a leap year or not.");

printf("\n\n Enter Number : ");
scanf("%i", &year);

//Logic to check leap year

if ((year % 400 == 0) || ( ( year % 100 != 0) && (year % 4 == 0 ))) {

printf("\n\n %i is a leap year!",year);
}
else {

printf("\n\n %i is not a leap year!!",year);
}

//getch();

}```

```

• Output :

C Program to Find Entered Year is a leap year or not.

Enter Number : 2014

2014 is not a leap year!!

C Program to Find Entered Year is a leap year or not.

Enter Number : 1900

1900 is not a leap year!!

C Program to Find Entered Year is a leap year or not.

Enter Number : 2000

2000 is a leap year!!

C Program to Find Entered Year is a leap year or not.

Enter Number : 2016

2016 is a leap year!!

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