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# 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 ``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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