C program to check if a year is Leap Year or Not

Write a C program to check if the given year is a Leap year or not.

What is a Leap Year? 🤔

“A leap year is always divisible by 4 except century years and a century year is a leap year only if it is divisible by 400.”

Tutorial 📺

Watch tutorial and learn how to solve this problem. 😉

Steps 🪜

To check if given year is Leap Year or not

1. Accept an integer from the user and store the value in a variable ‘year‘.
2. Now, validate by checking if the user has entered the valid year value between 1000 and 9999. If the year is not valid then print or display a message to the user, “You’ve entered INVALID YEAR value”.
3. After validating the year, check if year % 400 == 0 then the year is a leap year.
4. In else if part, check if year % 100 == 0 then print a message that “Year is not a leap year”.
5. Again, in the else if part, if year % 4 == 0 then print “Year is a leap year”.
6. Finally, in the else part display the message “Year is not a leap year”.

Code 💻

#include <stdio.h>
#include <conio.h>

void main()
{
  int year=0;
  clrscr();
  printf("Please enter the year: ");
  scanf("%d", &year);
  // Valid Year Range: 1000 - 9999
  if(year >= 1000 && year <= 9999)
  {
    if(year % 400 == 0)
      printf("\n%d is a LEAP YEAR.", year);
    else if(year % 100 == 0)
      printf("\n%d is not a LEAP YEAR.", year);
    else if(year % 4 == 0)
      printf("\n%d is a LEAP YEAR.", year);
    else
      printf("\n%d is not a LEAP YEAR.", year);
  }
  else {
    printf("\nYou've entered INVALID YEAR value.");
  }
  getch();
}

Example 😍

Let’s assume the user enters the value 120 which doesn’t fall in 1000 and 9999, thus a message will be displayed that “You’ve entered INVALID YEAR value”.

But, if the user enters 1992 then it is a valid year value because it falls between 1000 and 9999. Now, it will check whether the entered year value is a leap year or not.

First it will perform modulo operation and check if year % 400 == 0. Since 1992 modulo 400 is not equal to 0 then it will go to else-if statement to check if year % 100 == 0.

Again, 1992 modulo 100 is not equal to 0 so it will go to next else-if statement to check if year % 4 == 0, since 1992 modulo 4 is equal to 0 thus it will execute the printf statement and will display the message that “1992 is a LEAP YEAR“.

Let’s take another example where the user enters 1885, as we know it is a valid year since it falls between 1000 and 9999. It will move further to check if it a leap year or not.

First it will perform modulo operation and check if year % 400 == 0. Since 1885 modulo 400 is not equal to 0 then it will go to else-if statement to check if year % 100 == 0.

Again, 1885 modulo 100 is not equal to 0 so it will go to next else-if statement to check if year % 4 == 0, since 1885 modulo 4 is also not equal to 0 thus it will execute printf statement of else-part and will display the message that “1885 is not a LEAP YEAR“.

This is how we find out if the year is a Leap year or not.
For more C programs, click here.

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