Question

I’m having difficulties with a question from a past exam paper. I’m trying to multiply a from number to a n number. In other words: from*(from+1)(from+2)…*n.

I need to solve this problem by using a while loop. I have done this so far and not sure what to do. I know the code is wrong but have been stuck for a while.

public class Fact {

    public int last;

    private int factPartND(final int from, final int n) {
        int fromNum = from;
        int toNum = n;
        int result = 1;
        int c = 1;

        while (fromNum <= toNum) {  // e.g.5*6*7*8*9*10*11
            result = (fromNum) * (fromNum + c);  // calculate 5*6
            final int temp = result;  // store 5*6
            int result1 = temp * (fromNum + c);  // store 5*6*7*....
            c++;  // increments the fromNum in the while code
            fromNum++;  // increments 5 to 11 in the while condition
            last = result1;
        }
        return last;
    }

    public static void main(String[] args) {
        Fact f = new Fact();
        System.out.println(test);
    }
}

Answer 1

int result = 1;
for (int i = from; i <= to; i++) result *= i;
System.out.println("Result is " + result);

Strictly while:

int result = 1, i = from;
while (i <= to) result *= i++;
System.out.println("Result is " + result);