A leap year is a year that is divisible by 4 but not by 100, except if it is also divisible by 400. This ensures that our calendar stays aligned with the Earth’s revolutions around the Sun. In this article, we’ll explore three different ways to write a Leap Year program in C.

Learn different ways to write a “Leap Year program in C”

Method 1) Leap Year program in C using Simple Conditional Statements

This method involves straightforward if-else conditions to check the leap year criteria.

Code Example

#include <stdio.h>

int main() {
    int year;

    // Input year from user
    printf("Enter a year: ");
    scanf("%d", &year);

    // Check if the year is a leap year
    if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) {
        printf("%d is a leap year.\n", year);
    } else {
        printf("%d is not a leap year.\n", year);
    }

    return 0;
}

Explanation of the Code

1. Input Year: The user is prompted to enter a year, which is stored in the variable year.
2. Condition Check: The if statement checks two conditions:
   • If the year is divisible by 4 and not by 100.
   • If the year is divisible by 400.
3. Output: Based on the condition, the program prints whether the year is a leap year or not.

Method 2) Leap Year program in C using a Function to Check Leap Year

This method defines a function to determine if a year is a leap year, making the main function cleaner and more modular.

Code Example

#include <stdio.h>

// Function to check if a year is a leap year
int isLeapYear(int year) {
    if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) {
        return 1; // Leap year
    } else {
        return 0; // Not a leap year
    }
}

int main() {
    int year;

    // Input year from user
    printf("Enter a year: ");
    scanf("%d", &year);

    // Use the function to check if the year is a leap year
    if (isLeapYear(year)) {
        printf("%d is a leap year.\n", year);
    } else {
        printf("%d is not a leap year.\n", year);
    }

    return 0;
}

Explanation of the Code

1. Function Definition: The isLeapYear function encapsulates the logic to determine if a year is a leap year.
2. Input Year: Similar to the previous method, the user inputs a year.
3. Function Call: The isLeapYear function is called within the if statement to check the condition.
4. Output: The result is printed based on the function’s return value.

Method 3) Leap Year program in C using Ternary Operator

This method demonstrates the use of the ternary operator for a more compact solution.

Code Example

#include <stdio.h>

int main() {
    int year;

    // Input year from user
    printf("Enter a year: ");
    scanf("%d", &year);

    // Check leap year using ternary operator
    (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0) ? 
        printf("%d is a leap year.\n", year) : 
        printf("%d is not a leap year.\n", year);

    return 0;
}

Explanation of the Code

In this article, we explored three different methods to check if a year is a leap year using C programming: simple conditional statements, a dedicated function, and the ternary operator. Each method provides a unique approach to solving the problem, allowing you to choose the one that best fits your coding style and requirements. Understanding these methods enhances your programming skills and prepares you for more complex logical problems.