Print out even numbers with while-loop

[GetMeOuttaHere]

I am trying to write a program that prints out the even numbers between 1 and 21 using the WHILE loop. This is what I have, but there is no output. Why is that?

 #include <iostream>
using namespace std;

int main()
{
        int number = 1;

        while (number <= 21 && number / 2)
        {
                cout << number;
                number++;
        }
        return 0;
}

[keskiverto]

When is number / 2 true?

[GetMeOuttaHere]

I was trying to say when the number was even, but what would I set number / 2 equal to to make that work?

[TarikNeaj]

2 things.

1. The reason nothing is being outputted is that, number starts at 1, the condition is not met therefore it will never enter the while loop, and therefore it will never become 2, which would make the condition true.

I was trying to say when the number was even

2. You want to use the modulus operator here, otherwise you will get incorrect results -

http://www.cprogramming.com/tutorial/modulus.html

This is how I would do it -

#include <iostream>
using namespace std;

int main()
{
	int number = 1;

	while (number <= 21)
	{
		if (number % 2 == 0)
		{
			cout << number;
		}
		number++;
	}
	
	return 0;
}

[GetMeOuttaHere]

That makes more sense, but whenever I try to run your code, I'm still not having any output.

[TarikNeaj]

Works perfectly fine on visual studio 2013/2015 and on cpp.sh.

http://cpp.sh/6wrr

[Chervil]

This is another way:

#include <iostream>
using namespace std;

int main()
{
    const int start  = 1;
    const int finish = 21;
    
    int number = start;
    if (number % 2) number++;

    while (number <= finish)
    {
        cout << number << ' ';
        number += 2;
    }
    
    return 0;
}

[GetMeOuttaHere]

Okay, I got it now! Thank you everyone!