Question

I tried the following challenge:

Given the first few factorials:

1! = 1

2! = 2 x 1 = 2

3! = 3 x 2 x 1 = 6

4! = 4 x 3 x 2 x 1 = 24

What is the sum of the first 15 factorials, NOT INCLUDING 0!?

My solution in Java is the following:

public class Factorial
{
   public static void main(String[] args)
   {
     int sum = 0;    
     int multi = 1;
        for (int i=1;i<=15;i++)         
        {
        multi = multi*i;
        sum = multi+sum;     
        }     
     System.out.print(sum);
   }
}

I verified the solutions for the first 7 factorials but will it work for the first 15?

Answer 1

No, its not working for 15. Use long. Also, you could move the print statement inside the loop, to check from where it starts failing. I guess in this case it’s 13.