Find the average of first N natural numbers

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

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 <bits/stdc++.h> ` `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

`<?php ` `// PHP Program to find ` `// the Average of first ` `// n natural numbers ` ` ` `// Return the average ` `// of first n natural ` `// numbers ` `function` `avgOfFirstN(` `$n` `) ` `{ ` ` ` `return` `(float)(1 + ` `$n` `) / 2; ` `} ` ` ` `// Driver Code ` `$n` `= 20; ` `echo` `(avgOfFirstN(` `$n` `)); ` ` ` `// This code is contributed by Ajit. ` `?> ` |

Output:

10.5

** Time Complexity : O(1) **

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