Program for average of an array (Iterative and Recursive)

Given an array, the task is to find average of that array. Average is the sum of array elements divided by the number of elements.

Examples :

Input : arr[] = {1, 2, 3, 4, 5}
Output : 3
Sum of the elements is 1+2+3+4+5 = 15 
and total number of elements is 5.
So average is 15/5 = 3

Input : arr[] = {5, 3, 6, 7, 5, 3}
Output : 4.83333
Sum of the elements is 5+3+6+7+5+3 = 29
and total number of elements is 6.
So average is 29/6 = 4.83333.

Iterative:
Iterative program is easy. We need to find sum and divide sum by total number of elements. 

C++

// C++ program to calculate average of array elements
#include <iostream>
using namespace std;

// Function that return average of an array.
double average(int a[], int n)
{
    // Find sum of array element
    int sum = 0;
    for (int i=0; i<n; i++)
       sum += a[i];

    return (double)sum/n;
}

// Driver code
int main()
{
    int arr[] = {10, 2, 3, 4, 5, 6, 7, 8, 9};
    int n = sizeof(arr)/sizeof(arr[0]);

    cout << average(arr, n) << endl;
    return 0;
}

Java

// Java program to calculate average of array elements
class GFG {

    // Function that return average of an array.
    static double average(int a[], int n)
    {

        // Find sum of array element
        int sum = 0;

        for (int i = 0; i < n; i++)
            sum += a[i];

        return (double)sum / n;
    }

    //driver code
    public static void main (String[] args)
    {

        int arr[] = {10, 2, 3, 4, 5, 6, 7, 8, 9};
        int n = arr.length;

        System.out.println(average(arr, n));
    }
}

// This code is contributed by Anant Agarwal.

Python3

# Python3 code to calculate
# average of array elements

# Function that return
# average of an array.
def average( a , n ):

    # Find sum of array element
    sum = 0
    for i in range(n):
        sum += a[i]

    return sum/n;

# Driver code
arr = [10, 2, 3, 4, 5, 6, 7, 8, 9]
n = len(arr)
print(average(arr, n))

# This code is contributed by "Shard_Bhardwaj".

C#

// C# program to calculate average of
// array elements
using System;
class GFG {

    // Function that return average of
    // an array.
    static double average(int []a, int n)
    {

        // Find sum of array element
        int sum = 0;

        for (int i = 0; i < n; i++)
            sum += a[i];

        return (double)sum / n;
    }

    // Driver code
    public static void Main ()
    {

        int []arr = {10, 2, 3, 4, 5, 6,
                                7, 8, 9};
        int n = arr.Length;

        Console.Write(average(arr, n));
    }
}

// This code is contributed by nitin mittal.

PHP

<?php
// PHP program to calculate average
// of array elements

// Function that return average of
// an array.
function average( $a, $n)
{

    // Find sum of array element
    $sum = 0;
    for ( $i = 0; $i < $n; $i++)
        $sum += $a[$i];

    return $sum / $n;
}

// Driver code
    $arr = array(10, 2, 3, 4, 5,
                        6, 7, 8, 9);
    $n = count($arr);

    echo average($arr, $n);

// This code is contributed by anuj_67.
?>

Javascript

<script>
      // JavaScript program to calculate average of array elements

      // Function that return average of an array.
      function average(a, n)
      {

        // Find sum of array element
        var sum = 0;
        for (var i = 0; i < n; i++) sum += a[i];

        return parseFloat(sum / n);
      }

      // Driver code

      var arr = [10, 2, 3, 4, 5, 6, 7, 8, 9];
      var n = arr.length;

      document.write(average(arr, n));
      document.write("<br>");

      // This code is contributed by rdtank.
    </script>

Output

6

Time Complexity: O(n)

Auxiliary Space: O(1)

Recursive:
The idea is to pass index of element as an additional parameter and recursively compute sum. After computing sum, divide the sum by n.

C++

// C++ program to calculate average of array elements
#include <iostream>
using namespace std;

// Recursively computes average of a[]
double avgRec(int a[], int i, int n)
{
    // Last element
    if (i == n-1)
        return a[i];

    // When index is 0, divide sum computed so
    // far by n.
    if (i == 0)
        return ((a[i] + avgRec(a, i+1, n))/n);

    // Compute sum
    return (a[i] + avgRec(a, i+1, n));
}

// Function that return average of an array.
double average(int a[], int n)
{
     return avgRec(a, 0, n);
}

// Driver code
int main()
{
    int arr[] = {10, 2, 3, 4, 5, 6, 7, 8, 9};
    int n = sizeof(arr)/sizeof(arr[0]);

    cout << average(arr, n) << endl;
    return 0;
}

Java

// Java program to calculate average
// of array elements

class CalcAvg
{
    // Recursively computes average of a[]
    static double avgRec(int a[], int i, int n)
    {
        // Last element
        if (i == n-1)
            return a[i];

        // When index is 0, divide sum computed so
        // far by n.
        if (i == 0)
            return ((a[i] + avgRec(a, i+1, n))/n);

        // Compute sum
        return (a[i] + avgRec(a, i+1, n));
    }

    // Function that return average of an array.
    static double average(int a[], int n)
    {
         return avgRec(a, 0, n);
    }

    // main function
    public static void main (String[] args)
    {
        int arr[] = {10, 2, 3, 4, 5, 6, 7, 8, 9};
        int n = arr.length;

        System.out.println(average(arr, n));
    }
}

Python3

# Python3 code to calculate
# average of array elements

# Recursively computes average of a[]
def avgRec( a , i , n ):

    # Last element
    if i == n-1:
        return a[i]

    # When index is 0, divide sum
    # computed so far by n.
    if i == 0:
        return ((a[i] + avgRec(a, i+1, n)) / n)

    # Compute sum
    return (a[i] + avgRec(a, i+1, n))

# Function that return
# average of an array.
def average(a, n):
    return avgRec(a, 0, n)

# Driver code
arr = [10, 2, 3, 4, 5, 6, 7, 8, 9]
n = len(arr)
print(average(arr, n))

# This code is contributed by "Sharad_Bhardwaj".

C#

// C# program to calculate average
// of array elements
using System;

class GFG {

    // Recursively computes average of a[]
    static double avgRec(int []a, int i, int n)
    {

        // Last element
        if (i == n-1)
            return a[i];

        // When index is 0, divide sum
        // computed so far by n.
        if (i == 0)
            return ((a[i] + avgRec(a, i+1, n))/n);

        // Compute sum
        return (a[i] + avgRec(a, i+1, n));
    }

    // Function that return average of an array.
    static double average(int []a, int n)
    {
        return avgRec(a, 0, n);
    }

    // main function
    public static void Main ()
    {
        int []arr = {10, 2, 3, 4, 5, 6, 7, 8, 9};
        int n = arr.Length;

        Console.Write(average(arr, n));
    }
}

// This code is contributed by Smitha.

PHP

<?php
// PHP program to calculate
// average of array elements

// Recursively computes
// average of a[]
function avgRec($a, $i, $n)
{
    // Last element
    if ($i == $n - 1)
        return $a[$i];

    // When index is 0, divide
    // sum computed so far by n.
    if ($i == 0)
        return (($a[$i] +
                 avgRec($a, $i +
                         1, $n)) / $n);

    // Compute sum
    return ($a[$i] +
            avgRec($a, $i + 1, $n));
}

// Function that return
// average of an array.
function average($a, $n)
{
    return avgRec($a, 0, $n);
}

// Driver code
$arr = array(10, 2, 3, 4,
             5, 6, 7, 8, 9);
$n = sizeof($arr);

echo average($arr, $n) ;

// This code is contributed by Anuj_67
?>

Javascript

<script>

// Java script  program to calculate average
// of array elements

// Recursively computes average of a[]
function avgRec(a, i, n)
{

    // Last element
    if (i == n - 1)
        return a[i];

    // When index is 0, divide sum computed so
    // far by n.
    if (i == 0)
        return ((a[i] + avgRec(a, i + 1, n)) / n);

    // Compute sum
    return (a[i] + avgRec(a, i + 1, n));
}

// Function that return average of an array.
function average(a, n)
{
    return avgRec(a, 0, n);
}

// Driver code
let arr = [ 10, 2, 3, 4, 5, 6, 7, 8, 9 ];
let n = arr.length;

document.write(average(arr, n));

// This code is contributed by sravan kumar G

</script>

Output

6

Time Complexity: O(n)

Auxiliary Space: O(n)

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