Calculating Factorials in C# - No Errors, But Doesn't Work?

Question

I have a simple program that is supposed to calculate the factorial of an entered number. It says I have no errors, but when I run the program it stalls and does not work. Can someone please tell me why?

    private void getFactorial_Click(object sender, EventArgs e)
    {
        int userNumber, numberFactorial = 1;

        userNumber = int.Parse(numberInput.Text);
        if (userNumber <= 0)
        {
            numberOutput.Text = numberFactorial.ToString();
        }
        else
        {
            for (int i = 1; 1 <= userNumber; i++)
            {
                numberFactorial = numberFactorial * i;
                numberOutput.Text = numberFactorial.ToString();
            }
        }
    }
}

}

it works now dreamlax. I had typed "1" where I needed to use "i" in my for loop. That was the issue. Thanks for the reply though — Learnin2Code, Oct 07 '13 at 00:37
Side note: before you ask next one on this topic (like "why I get bad answer for 35") please check out http://stackoverflow.com/questions/13222207/why-computing-factorial-of-realtively-small-numbers-34-returns-0/13222515#13222515 — Alexei Levenkov, Oct 07 '13 at 02:12

score 4 · Accepted Answer · answered Oct 07 '13 at 00:19

4

It's always the simple things that get us.

In your loop you have this:

for (int i = 1; 1 <= userNumber; i++)

I believe you mean this:

for (int i = 1; i <= userNumber; i++)

In the conditional part of the loop you used a '1' rather than 'i'.

answered Oct 07 '13 at 00:19

Dweeberly

4,668
2
22
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Yes. Thank you very much. That was the problem – Learnin2Code Oct 07 '13 at 00:20

score 3 · Answer 2 · answered Oct 07 '13 at 00:15

3

Your conditional is off for your for loop. I think you want i <= userNumber.

for (int i = 1; i <= userNumber; i++)

answered Oct 07 '13 at 00:15

Daniel A. White

187,200
47
362
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1

Ah, YES!! Thank you. I did not catch that frustrating little mistake :) It works now – Learnin2Code Oct 07 '13 at 00:18

Calculating Factorials in C# - No Errors, But Doesn't Work?

2 Answers2