C Program Calculate Average N Numbers

How to Calculate the Average of N Numbers

The average (or arithmetic mean) of a set of numbers is calculated by summing all the numbers and then dividing by the count of numbers. Here's the step-by-step process:

1. Count how many numbers you have (N).
2. Sum all the numbers together.
3. Divide the total sum by N to get the average.

This calculation is useful in statistics, data analysis, and many other fields where you need to find a central value.

C Program Example

Here's a complete C program that calculates the average of N numbers entered by the user:

#include <stdio.h>

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

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

    while (n > 100 || n <= 0) {
        printf("Error! Number should be between 1 to 100. Please enter again: ");
        scanf("%d", &n);
    }

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

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

    return 0;
}

This program:

1. Declares variables to store the count of numbers, an array to hold the numbers, and variables for sum and average.
2. Prompts the user to enter the number of elements (N).
3. Validates that N is between 1 and 100.
4. Uses a loop to collect all N numbers from the user.
5. Calculates the sum of all numbers.
6. Computes the average by dividing the sum by N.
7. Prints the result with 2 decimal places.

The Formula

Where:

• Sum of all numbers = num1 + num2 + num3 + ... + numN
• N = Total count of numbers

Worked Example

Let's calculate the average of these 5 numbers: 12, 15, 18, 20, 25.

1. Count of numbers (N) = 5
2. Sum = 12 + 15 + 18 + 20 + 25 = 90
3. Average = 90 / 5 = 18.00

The average of these numbers is 18.00.