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

• Difficulty Level : Basic
• Last Updated : 12 Jul, 2022

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 ` `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 `   `// 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

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## Javascript

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Output:

`2.283333`

Time Complexity: O(n)

Auxiliary Space: O(1), since no extra space has been taken.

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