In the previous article we have discussed about Java Program to Find the Sum of Series 1 + (1/3) + (1/5) + … + N

In this article we are going to see how to print sum of the series (1/2) + (2/3) + (3/4) + …… + N by using Java programming language.

## Java Program to Find the Sum of Series (1/2) + (2/3) + (3/4) + …… + N

On observing the pattern carefully, we can see each term is in `a/b`

format.

Numerator = Starts from 1 and in each term incremented by 1

Denominator = In each term Numerator+1

Like

1st term=1/2

2nd term=2/3

3rd term=3/4 like this.

And the series= 1/2+2/3+3/4 like this.

And our task is to first form the series and then find the sum of the series.

Let’s see different ways to print sum of the series (1/2) + (2/3) + (3/4) + …… + N.

**Example:**

Suppose value of n = 3 (1/2) + (2/3) + (3/4) = 0.5+0.66+0.75 = 1.91

### Method-1: Java Program to Find the Sum of Series (1/2) + (2/3) + (3/4) + …… + N By Using For Loop

**Approach:**

- Declare an integer variable say ‘
`n`

’ which holds the value of Nth term. - Create Scanner class object.
- Prompt the user to enter a number as value of
`n`

. - Declare an long variable say ‘
`sum`

‘ and initialize it to 0. - Use a for loop
`from i=1 to i<=100`

(incremented by 1) - Inside the for loop, find each term and add it to
`sum`

. - Print the result.

**Program:**

import java.util.*; public class Main { public static void main(String [] args) { //creating object of Scanner class Scanner s = new Scanner(System.in); //Taking input of number of elements in the series System.out.println("Enter the value of 'n' "); int n = s.nextInt(); double sum = 0; //for loop to print the series for (int i = 1; i <= n; i++) { sum += ( i/(double)(i+1)); } System.out.println("Sum of the series is " + sum); } }

Output: Enter the value of 'n' 3 Sum of the series is 1.9166666666666665

### Method-2: Java Program to Find the Sum of Series (1/2) + (2/3) + (3/4) + …… + N By Using While Loop

**Approach:**

- Declare an integer variable say ‘
`n`

’ which holds the value of Nth term. - Create Scanner class object.
- Prompt the user to enter a number as value of
`n`

. - Declare an long variable say ‘
`sum`

‘ and initialize it to 0. - Use a for loop
`from i=1 to i<=100`

(incremented by 1) - Inside the for loop, find each term and add it to
`sum`

. - Print the result.

**Program:**

import java.util.*; public class Main { public static void main(String [] args) { //creating object of Scanner class Scanner s = new Scanner(System.in); //Taking input of number of elements in the series System.out.println("Enter the value of 'n' "); int n = s.nextInt(); double sum = 0; int i=1; //while loop to print the series while (i <= n) { sum += ( i/(double)(i+1)); i++; } System.out.println("Sum of the series is " + sum); } }

Output: Output: Enter the value of 'n' 3 Sum of the series is 1.9166666666666665

### Method-3: Java Program to Find the Sum of Series (1/2) + (2/3) + (3/4) + …… + N By Using While Loop

**Approach:**

- Declare an integer variable say ‘
`n`

’ which holds the value of Nth term. - Create Scanner class object.
- Prompt the user to enter a number as value of
`n`

. - Then call a user defined method say
`printSeries()`

by passing`n`

as parameter. - Inside method declare an long variable say ‘
`sum`

‘ and initialize it to 0. - Use a for loop
`from i=1 to i<=100`

(incremented by 1) - Inside the for loop, find each term and add it to
`sum`

. - Print the result.

**Program:**

import java.util.*; public class Main { public static void main(String[] args) { // creating object of scanner class Scanner s = new Scanner(System.in); //Taking input of number of elements in the series System.out.println("Enter the value of 'n' "); int n = s.nextInt(); //calling printSeries() method to print the series printSeries(n); } public static void printSeries(int n) { double sum = 0; //for loop to print the series for (int i = 1; i <= n; i++) { sum += ( i/(double)(i+1)); } System.out.println("Sum of the series is " + sum); } }

Output: Enter the value of 'n' 5 Sum of the series is 3.5500000000000003

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