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Thread: Sum of Factorials

  1. #1
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    Default Sum of Factorials

    Hi, I'm working on this code right now. The first method returns the factorial of an integer (factorial of 3 = 1x2x3). And the second returns the sum of the factorials between 2 integers. This is correct according to my professor. I'm just confused as to why in the 2nd methods it isn't "total = total + Factorial(i);" instead of what I have.

    thanks for the help.

    public class LoopProblems
    {
        public int Factorial (int n){ 
     
            int total = 1;
     
            for (int i = 1; i <= n ; i++ ) {
     
                total = total * i;
            }
            return total;
     
        }
     
        public int SumOfFactorials (int start, int end) {
     
            int total = 1;
     
            for (int i = start; i <= end ; i++ ) {
     
                total = total * Factorial(i);
            }
            return total;
     
        } 
    }


  2. #2
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    Default Re: Sum of Factorials

    What is the output from when the posted code is executed?
    x * 0 = 0
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Sum of Factorials

    So I changed it to 1. Is the code correct now?

    Thanks!

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    Default Re: Sum of Factorials

    Is the code correct now?
    Hard to tell without testing it.
    What happens when you compile and execute it?
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Sum of Factorials

    I'm not quite sure how to do that yet. We're not quite there yet in class. I'm going to teach myself how to do that soon. We just kind of work it out logically. To me , it should be
    total = total + Factorial(i);
    Thanks!

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    Default Re: Sum of Factorials

    Please post your code in code or highlight tags.

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    Default Re: Sum of Factorials

    Yeah. According to me too it should be (total = total + Factorial(i) because "total = total * Factorial(i);" doesnt make any logical sense relating to your question.

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