Leap Year Checker Program in Python

This document provides a Python program to determine whether a given year is a leap year. A leap year is a year that is divisible by 4, but years divisible by 100 are not leap years unless they are also divisible by 400.

Program Structure

The program follows these steps:

1. Accepts a year as input from the user.
2. Checks if the year is divisible by 4.
3. If the year is divisible by 4, further checks if it is also divisible by 100.
4. If the year is divisible by 100, checks if it is also divisible by 400.
5. Prints whether the year is a leap year or not based on the conditions.

Python Code

def is_leap_year(year):
    """
    Check if a given year is a leap year.

    A year is a leap year if:
    - It is divisible by 4, and
    - It is not divisible by 100, unless
    - It is also divisible by 400.

    Args:
    year (int): The year to check.

    Returns:
    bool: True if the year is a leap year, False otherwise.
    """
    if (year % 4 == 0):
        if (year % 100 == 0):
            if (year % 400 == 0):
                return True
            else:
                return False
        else:
            return True
    else:
        return False

def main():
    """
    Main function to execute the leap year checker.
    """
    try:
        year = int(input("Enter a year: "))
        if is_leap_year(year):
            print(f"{year} is a leap year.")
        else:
            print(f"{year} is not a leap year.")
    except ValueError:
        print("Please enter a valid integer year.")

if __name__ == "__main__":
    main()
    

Explanation

The is_leap_year function implements the leap year logic:

• If a year is divisible by 4, it’s a potential leap year.
• If it’s also divisible by 100, it must be divisible by 400 to be a leap year.
• Otherwise, it’s not a leap year.

The main function handles user input and output:

• It prompts the user to enter a year.
• It calls the is_leap_year function and prints whether the year is a leap year.
• It includes error handling for invalid input.