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

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 <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)

My Personal Notes

Suggest a Topic

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

C++

Java

Python3

C#

PHP

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