How to Determine the Leap Year?

A Leap year occurs mostly every 4 years, but every 100 years, we skip a leap year, unless it is divisible by 400.

Leap Year Algorithm

if (year is not divisible by 4) then (it is a common year)
else if (year is not divisible by 100) then (it is a leap year)
else if (year is not divisible by 400) then (it is a common year)
else (it is a leap year)

How to Test Leap Year in C++?

bool isLeap(int Y) {
    if (Y % 400 == 0) {
        return true;
    } else if ( Y % 100 == 0) {
        return false;
    } else if (Y % 4 == 0) {
        return true;
    } else {
        return false;
    }        
}

Or shorter:

bool isLeap(int Y) {
  return (Y % 400 == 0) || ((Y % 100 != 0) && (Y % 4 == 0));
}

How to Test Leap Year in C?

int isLeap(int Y) {
    if (Y % 400 == 0) {
        return true;
    } else if ( Y % 100 == 0) {
        return false;
    } else if (Y % 4 == 0) {
        return true;
    } else {
        return false;
    }        
}

Or shorter:

int isLeap(int Y) {
  return (Y % 400 == 0) || ((Y % 100 != 0) && (Y % 4 == 0));
}

How to Test Leap Year in Java?

boolean isLeap(int Y) {
    if (Y % 400 == 0) {
        return true;
    } else if ( Y % 100 == 0) {
        return false;
    } else if (Y % 4 == 0) {
        return true;
    } else {
        return false;
    }        
}

Or shorter:

boolean isLeap(int Y) {
    return (Y % 400 == 0) || ((Y % 100 != 0) && (Y % 4 == 0));
}

How to Test Leap Year in Javascript?

var isLeap = function(Y) {
    if (Y % 400 == 0) {
        return true;
    } else if ( Y % 100 == 0) {
        return false;
    } else if (Y % 4 == 0) {
        return true;
    } else {
        return false;
    }        
}

Or shorter:

var isLeap = function(Y) {
    return (Y % 400 == 0) || ((Y % 100 != 0) && (Y % 4 == 0));    
}

How to Test Leap Year in Python/Python3?

def isLeap(Y):
    if Y % 400 == 0:
        return True
    elif Y % 100 == 0:
        return False
    elif Y % 4 == 0:
        return True
    else:
        return False

or shorter:

def isLeap(Y):
    return (Y % 400 == 0) or ((Y % 100 != 0) and (Y % 4 == 0))  

All Leap Year Algorithms run at O(1) time and O(1) constant space.

–EOF (The Ultimate Computing & Technology Blog) —