C Programs Tutorials | IT Developer
IT Developer

Java Programs

Share with a Friend
Previous
HOME
Next

Menu driven - Sum of Series Program - Java Programs

Write a menu-driven program to find the sum of the following series depending on the user choosing 1 or 2:
1. s = 1/4 + 1/8 + 1/12 + … up to N terms.
2. s = 1/1! – 2/2! + 3/3! – … up to N terms.

where ! stands for factorial of the number and the factorial value of a number is the product of all integers from 1 to that number, e.g. 5! = 1 × 2 × 3 × 4 × 5 = 120. Use switch-case.

Java 

import java.io.*;
class Menu{
    public static void main(String args[])throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("1. 1/4 + 1/8 + 1/12 + ... N terms");
        System.out.println("2. 1/1! - 2/2! + 3/3! - ... N terms");
        System.out.print("Enter your choice: ");
        int choice = Integer.parseInt(br.readLine());
        switch(choice){
            case 1:
            System.out.print("N = ");
            int n = Integer.parseInt(br.readLine());
            double sum = 0.0;
            for(int i = 1; i <= n; i++)
                sum += 1.0 / (4 * i);
            System.out.println("Sum = " + sum);
            break;
            case 2:
            System.out.print("N = ");
            n = Integer.parseInt(br.readLine());
            sum = 0.0;
            int sign = 1;
            for(int i = 1; i <= n; i++){
                int f = 1;
                for(int j = 1; j <= i; j++)
                    f *= j;
                sum += sign * (double)i / f;
                if(sign == 1)
                    sign = -1;
                else
                    sign = 1;
            }
            System.out.println("Sum = " + sum);
            break;
            default:
            System.out.println("Invalid choice!");
        }
    }
}

Output

 
 OUTPUT 1: 
1. 1/4 + 1/8 + 1/12 + ... N terms
2. 1/1! - 2/2! + 3/3! - ... N terms
Enter your choice: 1
N = 10
Sum = 0.7322420634920634 

 OUTPUT 2: 
1. 1/4 + 1/8 + 1/12 + ... N terms
2. 1/1! - 2/2! + 3/3! - ... N terms
Enter your choice: 2
N = 10
Sum = 0.3678791887125221
Previous
Next