'Multiply numbers for loop java returning 0

I'm trying to take a number(n) and multiply it by every number before it, enter 4 you get (1x2x3x4) = 24. My code returns a 0. I have an addition just like this that works. Any ideas?

public static int multiplyTooNum() 
    {
        Scanner myIn = new Scanner(System.in);          
        int n;
                    
        System.out.println("Please enter a number");    
        n = myIn.nextInt();
        myIn.nextLine();
        int sum = 0;
        
        for (int i=0; i<n; i++)
        {
            sum = sum * i;
        }                   
        
        int result = sum*n;
        System.out.println(result);
        myIn.close();
        return result;
    }
javanumbersreturnmultiplication


Solution 1:[1]

In multiplication, the accumulated variable is not called sum. It is called product. The word sum is only used in the context of addition.

Now, on with your problem:

If you remember your elementary school mathematics, anything multiplied by zero gives zero.

That's why you are receiving a zero in the end.

So, in order to fix this, you have to initialize your product with 1 instead of 0, and then make your for loop start counting from index 1 instead of 0.

Solution 2:[2]

    for (int i=0; i<n; i++)
    {
        sum = sum * i;
    }

Issue is in this part, you start i from 0, so each time the sum get's 0 and it will be multiplied again. I suggest you to learn debugging and step over in loops to pinpoint the issues.

Sources

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Source: Stack Overflow

Solution Source
Solution 1
Solution 2 Juliyanage Silva

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