C Program to Calculate Average Using Arrays

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

Store Numbers and Calculate Average Using Arrays

#include <stdio.h>
int main() {
    int n, i;
    float num[100], sum = 0.0, avg;

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

    while (n > 100 || n < 1) {
        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];

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

Here, the user is first asked to enter the number of elements. This number is assigned to n.

If the user entered integer is greater less than 1 or greater than 100, the user is asked to enter the number again. This is done using a while loop.

Then, we have iterated a for loop from i = 0 to i . In each iteration of the loop, the user is asked to enter numbers to calculate the average. These numbers are stored in the num[] array.

scanf("%f", &num[i]);

And, the sum of each entered element is computed.

sum += num[i];

Once the for loop is completed, the average is calculated and printed on the screen.

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