Program to find sum of series 1 + 1/2 + 1/3 + 1/4 + .. + 1/n

If inverse of a sequence follows rule of an A.P i.e, Arithmetic progression, then it is said to be in Harmonic Progression.In general, the terms in a harmonic progression can be denoted as : 1/a, 1/(a + d), 1/(a + 2d), 1/(a + 3d) …. 1/(a + nd).
As Nth term of AP is given as ( a + (n – 1)d) .Hence, Nth term of harmonic progression is reciprocal of Nth term of AP, which is : 1/(a + (n – 1)d)
where “a” is the 1st term of AP and “d” is the common difference.

We can use a for loop to find sum.

C++

// C++ program to find sum of series 
#include <iostream> 
using namespace std; 
  
// Function to return sum of  
// 1/1 + 1/2 + 1/3 + ..+ 1/n 
class gfg 
{ 
      
public : double sum(int n) 
{ 
    double i, s = 0.0; 
    for (i = 1; i <= n; i++) 
    s = s + 1/i; 
    return s; 
} 
}; 
  
// Driver code 
int main() 
{ 
    gfg g; 
    int n = 5; 
    cout << "Sum is " << g.sum(n); 
    return 0; 
} 
  
// This code is contributed by SoM15242. 

C

// C program to find sum of series 
#include <stdio.h> 
  
// Function to return sum of 1/1 + 1/2 + 1/3 + ..+ 1/n 
double sum(int n) 
{ 
  double i, s = 0.0; 
  for (i = 1; i <= n; i++) 
      s = s + 1/i; 
  return s; 
} 
  
int main() 
{ 
    int n = 5; 
    printf("Sum is %f", sum(n)); 
    return 0; 
}

Java

// Java Program to find sum of series 
import java.io.*; 
  
class GFG { 
      
    // Function to return sum of 
    // 1/1 + 1/2 + 1/3 + ..+ 1/n 
    static double sum(int n) 
    { 
      double i, s = 0.0; 
      for (i = 1; i <= n; i++) 
          s = s + 1/i; 
      return s; 
    } 
   
     
    // Driven Program 
    public static void main(String args[]) 
    { 
        int n = 5; 
        System.out.printf("Sum is %f", sum(n)); 
          
    } 
} 
  
// This code is contributed by Nikita Tiwari. 

Python3

# Python program to find the sum of series 
  
def sum(n): 
    i = 1
    s = 0.0
    for i in range(1, n+1): 
        s = s + 1/i; 
    return s; 
  
# Driver Code  
n = 5
print("Sum is", round(sum(n), 6)) 
  
# This code is contributed by Chinmoy Lenka 

C#

// C# Program to find sum of series 
using System; 
  
class GFG { 
      
    // Function to return sum of 
    // 1/1 + 1/2 + 1/3 + ..+ 1/n 
    static float sum(int n) 
    { 
        double i, s = 0.0; 
          
        for (i = 1; i <= n; i++) 
            s = s + 1/i; 
              
        return (float)s; 
    } 
  
      
    // Driven Program 
    public static void Main() 
    { 
        int n = 5; 
          
        Console.WriteLine("Sum is "
                           + sum(n)); 
          
    } 
} 
  
// This code is contributed by vt_m. 

PHP

<?php 
// PHP program to find sum of series 
  
// Function to return sum of 
// 1/1 + 1/2 + 1/3 + ..+ 1/n 
function sum( $n) 
{ 
    $i; 
    $s = 0.0; 
    for ($i = 1; $i <= $n; $i++) 
        $s = $s + 1 / $i; 
    return $s; 
} 
  
    // Driver Code 
    $n = 5; 
    echo("Sum is "); 
    echo(sum($n)); 
      
//This code is contributed by vt_m 
?> 

Output:

2.283333

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C++

C

Java

Python3

C#

PHP

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