# Java Program to Find the Sum of Series 1 + (1/3) + (1/5) + … + N

In the previous article we have discussed about Java Program to Find the Sum of Series 1 + (1/2) + (1/3) + … + N

In this article we are going to see how to print sum of the series 1 + (1/3) + (1/5) + … + N by using Java programming language.

## Java Program to Find the Sum of Series 1 + (1/3) + (1/5) + … + N

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

Numerator = 1 (Fixed)

Denominator = Odd number starting from 1

Like

1st term=1/1

2nd term=1/2

3rd term=1/3 like this.

And the series= 1/1+1/2+1/3 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 + (1/3) + (1/5) + … + N.

Example:

Suppose value of n = 3

1 + (1/2) + (1/3) = 1 + 0.5 + 0.34 = 1.84

### Method-1: Java Program to Find the Sum of Series 1 + (1/3) + (1/5) + … + 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.
• Declare an integer variable ‘count‘ and initialize it to 1.
• Then declare integer variable m=n*n;
• Use a for loop from i=1 to i<=m (incremented by 2)
• Inside the for loop, find each term and add it to sum. Also keep track on count variable if count==n then break the loop.
• 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 count=1;
int m = n * n;
//for loop to print the series
for (int i = 1; i <= m; i += 2)
{
System.out.println (1.0 / i);
sum += (1.0 / i);
if(count == n)
break;
count++;
}
System.out.println ("Sum of the series is " + sum);
}
}

Output:

Enter the value of 'n'
3
1.0
0.3333333333333333
0.2
Sum of the series is 1.5333333333333332

### Method-2: Java Program to Find the Sum of Series 1 + (1/3) + (1/5) + … + 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.
• Declare an integer variable ‘count‘ and initialize it to 1.
• Then declare integer variable m=n*n;
• Declare an integer variable ‘i‘ and initialize it to 1.
• Use a while loop till i<=m (incremented by 2)
• Inside the while loop, find each term and add it to sum.  Also keep track on count variable if count==n then break the loop.
• 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 count=1;
int m = n * n;
int i=1;
//while loop to print the series
while (i <= m)
{
System.out.println (1.0 / i);
sum += (1.0 / i);
if(count == n)
break;
count++;
i+=2;
}
System.out.println ("Sum of the series is " + sum);
}
}


Output:

Enter the value of 'n'
3
1.0
0.3333333333333333
0.2
Sum of the series is 1.5333333333333332

### Method-3: Java Program to Find the Sum of Series 1 + (1/3) + (1/5) + … + 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.
• Declare an integer variable ‘count‘ and initialize it to 1.
• Then declare integer variable m=n*n;
• Use a for loop from i=1 to i<=m (incremented by 2)
• Inside the for loop, find each term and add it to sum.  Also keep track on count variable if count==n then break the loop.
• 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;
int count=1;
int m = n * n;
int i=1;
//for loop to print the series
while (i <= m)
{
System.out.println (1.0 / i);
sum += (1.0 / i);
if(count == n)
break;
count++;
i+=2;
}
System.out.println ("Sum of the series is " + sum);
}
}
Output:

Enter the value of 'n'
3
1.0
0.3333333333333333
0.2
Sum of the series is 1.5333333333333332

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