# 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

 ` `

Output:

```2.283333
```

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Improved By : vt_m, SoumikMondal

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