Answer :

#include<stdio.h>   //header file contains the function,decleraction and macro defination of key words used in code.

int main ()

{

int year;  //adressing the variables

printf("Enter an year you want");  //output

scanf("%d",&year);  //stores the input from the user

if (year%100==0) //condition  //nested if - else

{

if (year%400==0)  //condition

printf("%d is a leap year",year);  //output

}

else

{

if (year%4==0)  //condition

{

printf("%d is a leap year",year);  //output

}

}

}

Output :