Python: Determine whether a given year is a leap year

Last update on April 22 2025 12:49:20 (UTC/GMT +8 hours)

2. Leap Year Checker

Write a Python program to determine whether a given year is a leap year.

Sample Solution:

Python Code:

# Define a function named leap_year that takes a year (y) as input
def leap_year(y):
    # Check if the year is divisible by 400
    if y % 400 == 0:
        return True
    # Check if the year is divisible by 100 but not divisible by 400
    if y % 100 == 0:
        return False
    # Check if the year is divisible by 4 but not divisible by 100
    if y % 4 == 0:
        return True
    # If none of the above conditions are met, the year is not a leap year
    else:
        return False

# Print whether the year 1900 is a leap year or not using the leap_year function
print(leap_year(1900))

# Print whether the year 2004 is a leap year or not using the leap_year function
print(leap_year(2004))

Output:

False                                                                                                         
True

Explanation:

In the exercise above,

The above code defines a function named "leap_year()" that takes a year (denoted by 'y') as input.
Leap Year logic:

Inside the function, it checks if the year is divisible by 400. If it is, it returns 'True', indicating it's a leap year because leap years are evenly divisible by 400.
If the year is not divisible by 400, it checks if it's divisible by 100. If it is, it returns 'False' because years divisible by 100 but not by 400 are not leap years.
If the year is not divisible by 100, it checks if it's divisible by 4. If it is, it returns 'True', indicating it's a leap year because years divisible by 4 are leap years unless they are also divisible by 100 (as handled in the previous condition).
If none of the above conditions are met, it returns 'False', indicating it's not a leap year.

Finally "leap_year()" functiont tests two different years (1900 and 2004) and print the results.

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python program to check whether a given year is a leap year and also return the number of days in February for that year.
Write a Python function that takes a list of years and uses the filter function to return only the leap years.
Write a Python script that determines if a year is leap and then prints a message stating "Leap Year" or "Common Year" in uppercase.
Write a Python program that verifies leap years by checking divisibility rules and then computes the next leap year after a given year.

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