🚀 Day 12/150 – Check Leap Year in Python

 

Welcome back to the 150 Days of Python series! 🎯
Today, we’re solving a real-world logic problem — checking whether a year is a leap year.

This is a great exercise to understand:

• Conditional statements
• Logical operators (and, or)
• Writing clean, readable code

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 Problem Statement

Write a Python program to check whether a given year is a Leap Year or Not.

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 Understanding Leap Year Logic

Before coding, let’s understand the rules:

A year is a leap year if:

✔ Divisible by 4
❌ But NOT divisible by 100
✔ EXCEPTION: If divisible by 400, then it is a leap year

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Year Result
2024 ✅ Leap Year
1900 ❌ Not Leap Year
2000 ✅ Leap Year

 Method 1 – Using if-elif-else

year = 2024

if (year % 4 == 0 and year % 100 != 0) or (year % 400 == 0):
    print("Leap Year")
else:
    print("Not a Leap Year")

 Code Explanation:

• year % 4 == 0
  👉 Checks if year is divisible by 4
• year % 100 != 0
  👉 Ensures it is NOT divisible by 100
• year % 400 == 0
  👉 Special case: makes century years valid
• and → both conditions must be true
• or → at least one condition must be true

👉 This full condition ensures accurate leap year calculation

 Method 2 – Taking User Input

year = int(input("Enter a year: ")) if (year % 4 == 0 and year % 100 != 0) or (year % 400 == 0): print("Leap Year") else: print("Not a Leap Year")

🔍 What’s new here?

• input() → takes user input
• int() → converts string input into integer

👉 Always convert input when dealing with numbers!

Method 3 – Using a Function

def check_leap_year(year): if (year % 4 == 0 and year % 100 != 0) or (year % 400 == 0): return "Leap Year" else: return "Not a Leap Year" print(check_leap_year(2024))

🔍 Why use a function?

• Code becomes reusable
• Cleaner structure
• Easy to test

👉 You can call this function anytime with different values

Method 4 – Using Python calendar Module

import calendar year = 2024 if calendar.isleap(year): print("Leap Year") else: print("Not a Leap Year")

🔍 Explanation:

• calendar.isleap(year)
  👉 Built-in Python function
  👉 Returns True or False
  

👉 This is the simplest and most reliable method

Important Things to Remember

✔ Always use correct logical condition
✔ Don’t forget parentheses ( ) in conditions
✔ Convert input using int()
✔ Built-in functions save time and reduce errors

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Summary

Method	Concept
if-else	Basic logic
User Input	Real-world usage
Function	Reusability
calendar module	Pythonic approach