C Program to Calculate the Average of All Elements of an Array

Given an array arr of size N, the task is to calculate the average of all the elements of the given array.

Example 

Input: arr[] = {1, 2, 3, 4, 5}
Output: 3

Approach

1. We can simply find the sum of all elements of a given array.

2. Divide this sum by the total number of elements present in the array. 

Sum of the elements is = 1+2+3+4+5 = 15 
The total number of elements = 5.
Average = 15/5 = 3

Pseudocode

procedure average(arr)
  Declare sum as integer
  FOR EACH value in arr DO
     sum ← sum + arr[n]
  END FOR
  avg ← sum / size_of_array
  Display avg
end procedure

Program to Calculate Average of All Elements of an Array

Below is the C program to implement the above approach:

C

// C program to demonstrate
// average of array elements
#include <stdio.h>

// Function that return average
// of given array.
double average(int a[], int n)
{
    // Find the 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()
{
    // Input array
    int arr[] = { 1, 2, 3, 4, 5 };

    // Size of array
    int n = sizeof(arr) / sizeof(arr[0]);

    // average(arr, n) function is return the
    // average of the array.
    int avg = average(arr, n);

    // Display average of given array
    printf("Average = %d ", avg);
    return 0;
}

Output

Average = 3 

The complexity of the above method

Time Complexity: O(n)

Space Complexity: O(1)