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Find the average of first N natural numbers
• Last Updated : 25 Apr, 2018

Write a program to find the Average of first N natural number.
Examples:

```Input  : 10
Output : 5.5
1+2+3+4+5+6+7+8+9+10 = 5.5

Input  : 7
Output : 4.0
1+2+3+4+5+6+7 = 4
```

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Prerequisite : Sum of first n natural numbers.

As discussed in previous post, sum of n natural number n(n+1)/2, we find the Average of n natural number so divide by n is n(n+1)/2*n = (n+1)/2. Here 1 if first term and n is last term.

## C++

 `// CPP Program to find the Average of first ` `// n natural numbers ` `#include ` `using` `namespace` `std; ` ` `  `// Return the average of first n natural numbers ` `float` `avgOfFirstN(``int` `n) ` `{ ` `    ``return` `(``float``)(1 + n)/2; ` `} ` ` `  `// Driven Program ` `int` `main() ` `{ ` `    ``int` `n = 20; ` `    ``cout << avgOfFirstN(n) << endl; ` `    ``return` `0; ` `} `

## Java

 `// Java Program to find the Average of first ` `// n natural numbers ` `import` `java.io.*; ` ` `  `class` `GFG { ` ` `  `    ``// Return the average of first n  ` `    ``// natural numbers ` `    ``static` `float` `avgOfFirstN(``int` `n) ` `    ``{ ` `        ``return` `(``float``)(``1` `+ n) / ``2``; ` `    ``} ` ` `  `    ``// Driven Program ` `    ``public` `static` `void` `main(String args[]) ` `    ``{ ` `        ``int` `n = ``20``; ` `        ``System.out.println(avgOfFirstN(n)); ` `    ``} ` `} ` ` `  `/*This code is contributed by Nikita tiwari.*/`

## Python3

 `# Python 3 Program to find the Average  ` `# of first n natural numbers ` ` `  `# Return the average of first n ` `# natural numbers ` `def` `avgOfFirstN(n) : ` `    ``return` `(``float``)(``1` `+` `n) ``/` `2``; ` ` `  `# Driven Program ` `n ``=` `20` `print``(avgOfFirstN(n)) ` ` `  `# This code is contributed by Nikita Tiwari. `

## C#

 `// C#Program to find the Average of first ` `// n natural numbers ` `using` `System; ` ` `  `class` `GFG { ` ` `  `    ``// Return the average of first n  ` `    ``// natural numbers ` `    ``static` `float` `avgOfFirstN(``int` `n) ` `    ``{ ` `        ``return` `(``float``)(1 + n) / 2; ` `    ``} ` ` `  `    ``// Driven Program ` `    ``public` `static` `void` `Main() ` `    ``{ ` `        ``int` `n = 20; ` `        ``Console.WriteLine(avgOfFirstN(n)); ` `    ``} ` `} ` ` `  `/*This code is contributed by vt_m.*/`

## PHP

 ` `

Output:

```10.5
```

Time Complexity : O(1)

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