Check for Even Odd in C++

Check even or odd in C++ with n % 2. Remainder 0 is even.

BeginnerConditional ProgramsExample 1 of 4

check-for-even-odd.cpp

1#include <iostream>
2using namespace std;
3
4int main() {
5    int num;
6    
7    cout << "Enter a number: ";
8    cin >> num;
9    
10    if (num % 2 == 0) {
11        cout << num << " is even" << endl;
12    } else {
13        cout << num << " is odd" << endl;
14    }
15    
16    return 0;
17}

Output

Enter a number: 7
7 is odd

What's going on

This C++ program checks even vs odd with n % 2 == 0. Remainder 0 means even. That's the whole test.

#include <iostream>

Need it for cout and cin.

int num;

The value to test. Until cin fills it, don't print it.

cout << "Enter a number: ";

cin >> num;

Letters leave cin failed. Later the if then compares leftover junk.

if (num % 2 == 0)

% is remainder, not percent. 7 % 2 is 1, so odd. 8 % 2 is 0, so even.

Keep the == 0. if (num % 2) works because nonzero is true, and it's harder to read at 1 a.m.

Negatives: -3 % 2 is usually -1 in C++, not 1. == 0 still calls even numbers even. Don't rewrite the test to == 1 or -3 falls through the wrong branch.

0 is even. 0 % 2 == 0.

Sample: input 7 → remainder 1 → "7 is odd", which matches the output on this page.

NextLargest Among 3