Leap Year Calculator

Level: Beginner 15–30 min

Concepts: Validation

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Create a program to determine if a given year is a leap year.

Requirements

1. Implement leap year rules:
   • A year is a leap year if it is divisible by 4
   • However, if the year is divisible by 100, it is not a leap year
   • Unless the year is also divisible by 400, then it is a leap year
2. Handle input validation:
   • Input must be a positive integer
   • Input must be a valid year (e.g., not negative)
3. Return appropriate results:
   • Boolean indicating if the year is a leap year
   • Error message for invalid inputs

Test Cases

Year	Is Leap Year?	Reason
2000	Yes	Divisible by 400
2004	Yes	Divisible by 4, not by 100
2100	No	Divisible by 100, not by 400
2001	No	Not divisible by 4
0	Error	Invalid year
-1	Error	Invalid year

Edge Cases to Consider

• Year 0
• Negative years
• Non-integer inputs
• Very large years
• Null or undefined inputs

Tips

• Start with the basic divisible by 4 rule
• Add the divisible by 100 exception
• Finally add the divisible by 400 rule
• Consider using a separate method for input validation
• Use descriptive variable names for the rules