Question

Write a java program that asks the user for a number n and gives them the possibility to choose between computing the sum and computing the product of 1,…,n.

Example of running this program:

Enter an integer number n: __7________

Enter Sum or Product: __Sum__________________________________

Program output: Sum of 1 ... 7

Sum or Product: Sum

Sum = 28

Now second sample of second execution

Enter an integer number n: __5__________________________________

Enter Sum or Product: __Product__________________________________

Program output:  Product of 1 ... 5

Sum or Product: Product

Product = 120

Answer 1

import java.util.Scanner;

public class SumProduct {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter an integer number n: ");
        int n = in.nextInt();
        System.out.print("Enter Sum or Product: ");
        String choice = in.next();
        System.out.println("Program output: " + choice + " of 1 ... " + n);
        int result;
        if (choice.equalsIgnoreCase("Sum")) {
            result = 0;
            for (int i = 1; i <= n; i++)
                result += i;
        } else {
            result = 1;
            for (int i = 1; i <= n; i++)
                result *= i;
        }
        System.out.println("Sum or Product: " + choice);
        System.out.println(choice + " = " + result);
    }
}