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Find the average of first N natural numbers

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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.*/
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.*/
Javascript
<script>

// javascript Program to find the Average of first
// n natural numbers

// Return the average of first n natural numbers
function avgOfFirstN( n)
{
    return (1 + n)/2;
}

// Driven Program

    let n = 20;
    document.write(avgOfFirstN(n));

// This code is contributed by todaysgaurav 

</script>
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.
?>
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.

Output: 

10.5


Time Complexity: O(1)

Auxiliary Space: O(1) 



Last Updated : 14 Mar, 2024
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