WAP to compute the sum of the first n terms of the following series-CodePudding

S = 1 1/2! 1/3! 1/4!.....

Here is my code :

import java.util.Scanner;

public class question{
     public static void main(String[] args) {
     Scanner sc = new Scanner(System.in);
     int n =sc.nextInt();
     int[] fact= new int[n];
     fact[0] =fact[1] =1;
     for(int i=2;i<=n;i  )
     {
     fact[i]= fact[i-1]*i;
     }
     double sum=0;
     for(int i=1;i<=n;i  ){
     sum =1/fact[i];
      }
     System.out.println(sum);
   }
}

This code is giving error input:3 Exception in thread "main" java.lang.ArrayIndexOutOfBoindsException: Index 33 out of bounds for length 3 at question.main(question.java.12)

REASON..? For this error How to resolve it..?

CodePudding user response：

The array is one element too small, it should be

int[] fact = new int[n 1];

Also note that sum =1/fact[i] will be an integer division. You can use

sum  = 1.0/ fact[i]

to get a floating point division.

CodePudding user response：

Also you do not need to store the factorials in an array as the purpose is just to sum. You could do the following:

int fact = 1;
double sum = 0;
int n = 15;
for(int i = 1; i<=n; i  ){
   sum  = 1.0/fact;
   fact *= i;
}