C++ Program to Check if a Year is a Leap Year.

In this post, you will learn to check whether a year is a leap year or not using the C++ programming language. But before moving to the coding part it is important to get some basic understanding of Leap Year. Let's start this topic with our first question and that is:

What is Leap Year?

A Year that contains 366 days is known as Leap Year. We get one leap year every four years and this year February month contains 29 days which is one extra day than any usual year. Examples of Leap Years: 1968, 2000, 2004, 2012, etc.

How to Check if a Year is Leap Year or not?

There are certain conditions that you can check to find out whether a year is a leap year or not.

If the given year is divisible by 400 then it is a leap year.
If the given year is divisible by 100 but not divisible by 400 then it is not a leap year.

If the given year is divisible by 4 but is not divisible by 100 then it is a leap year.
If both the above conditions fail to satisfy then the given year is not a leap year.

C++ Program to check Leap Year using if else statement.

//C++ Code to check Leap year using if else.
#include<iostream>
using namespace std;

int main(){

    int year;

    cout<<"Enter a Year: ";
    cin>>year;

    //Year divisible by 400
    if(year % 400 == 0)
       cout<<year<<" is a Leap Year.";
    //Year divisible by 100 but not divisible by 400   
    else if(year % 100 == 0)
       cout<<year<<" is not a Leap Year.";
    //Year divisible by 4 but not divisible by 100   
    else if(year % 4 == 0)
       cout<<year<<" is a Leap Year.";
    else
       cout<<year<<" is not a Leap Year.";

    return 0;            
}

Output:

Enter a Year: 1968
1968  is a Leap Year.

C++ Program to check Leap Year using nested if else statement.

//C++ Code to check Leap year using nested if else.
#include<iostream>
using namespace std;

int main(){

    int year;

    cout<<"Enter a Year: ";
    cin>>year;

    if(year % 4 == 0){
        if(year % 100 == 0){
            if(year % 400 == 0){
                cout<<year<<" is a Leap Year.";
            }
            else{
                cout<<year<<" is not a Leap Year.";
            }
        }
        else{
            cout<<year<<" is a Leap Year.";
        }
    }
    else{
        cout<<year<<" is not a Leap Year.";
    }

    return 0;            
}

Output:

Enter a Year: 2006
2006  is not a Leap Year.

Here in the above program, first, check if the year is divisible by 4 or not if not divisible then the given year is not a leap year. If the year is divisible by 4 then check if it is divisible by 100 or not, if not divisible by 100 then it is a leap year else, not a leap year. If the year is divisible by 100 then it must be divisible by 400 to be a leap year.