In this example, if…else statement is used to check whether a number entered by the user is even or odd.

Integers which are perfectly divisible by 2 are called even numbers.

And those integers which are not perfectly divisible by 2 are not known as odd number.

To check whether an integer is even or odd, the remainder is calculated when it is divided by 2 using modulus operator %. If remainder is zero, that integer is even if not that integer is odd.

Example 1: Check Whether Number is Even or Odd using if else

#include <iostream>
using namespace std;

int main()
{
    int n;

    cout << "Enter an integer: ";
    cin >> n;

    if ( n % 2 == 0)
        cout << n << " is even.";
    else
        cout << n << " is odd.";

    return 0;
}

Output

Enter an integer: 23
23 is odd.

In this program, if..else statement is used to check whether n%2 == 0 is true or not. If this expression is true, n is even if not n is odd.

You can also use ternary operators ?: instead of if..else statement. Ternary operator is short hand notation of if…else statement.

Example 2: Check Whether Number is Even or Odd using ternary operators

#include <iostream>
using namespace std;

int main()
{
    int n;

    cout << "Enter an integer: ";
    cin >> n;
    
    (n % 2 == 0) ? cout << n << " is even." :  cout << n << " is odd.";
    
    return 0;
}