C Program to Calculate Average Using Arrays

This program takes n number of element from user (where, n is specified by user), stores data in an array and calculates the average of those numbers.

To understand this example, you should have the knowledge of following C programming topics:

Source Code to Calculate Average Using Arrays

#include <stdio.h>

int main()
    int n, i;
    float num[100], sum = 0.0, average;

    printf("Enter the numbers of elements: ");
    scanf("%d", &n);

    while (n > 100 || n <= 0)
        printf("Error! number should in range of (1 to 100).\n");
        printf("Enter the number again: ");
        scanf("%d", &n);

    for(i = 0; i < n; ++i)
        printf("%d. Enter number: ", i+1);
        scanf("%f", &num[i]);
        sum += num[i];

    average = sum / n;
    printf("Average = %.2f", average);

    return 0;


Enter the numbers of elements: 6
1. Enter number: 45.3
2. Enter number: 67.5
3. Enter number: -45.6
4. Enter number: 20.34
5. Enter number: 33
6. Enter number: 45.6
Average = 27.69

This program takes the number of elements in the array and stores in the variable n.

Then, the for loop gets all the elements from the user and stores the sum of the entered numbers in sum.

Finally, the average is calculated by dividing sum by the number of elements n.