C Exercises: Calculate and print average of the stream of given numbers

Last update on March 20 2025 12:36:08 (UTC/GMT +8 hours)

21. Running Average Calculation Variants

Write a C program to calculate and print the average (or mean) of a stream of given numbers.

Example 1:
Input:
arr[] = {10, 20, 30, 40, 50, 60, 70, 80, 90, 100}
Output:
Average of 1 numbers is 10.000000
Average of 2 numbers is 15.000000
Average of 3 numbers is 20.000000
Average of 4 numbers is 25.000000
Average of 5 numbers is 30.000000
Average of 6 numbers is 35.000000
Average of 7 numbers is 40.000000
Average of 8 numbers is 45.000000
Average of 9 numbers is 50.000000
Average of 10 numbers is 55.000000

Visual Presentation:

Sample Solution:

C Code:

#include <stdio.h>
#include <stdlib.h>

// Function to compute streaming average of an array
void streamAvg(float arr[], int arr_size) { 
    float avg = 0; // Variable to store the average
    int i = 0;

    // Loop through the array to compute streaming averages
    while (i < arr_size) { 
        avg = (avg * i + arr[i]) / (i + 1); // Update the average value
        printf("\nAverage of %d numbers is %f \n", i + 1, avg); // Print the streaming average
        i++;
    } 
    return; // End of function
} 

// Main function
int main(void) { 
    float arr[] = {10, 20, 30, 40, 50, 60, 70, 80, 90, 100}; // Array of floating point numbers
    int arr_size = sizeof(arr) / sizeof(arr[0]); // Calculate the size of the array
    printf("\nElements in array are: ");  

    int i = 0;
    // Print the elements in the array
    while (i < 10) {  
        printf("%f  ", arr[i]);  
        i++;
    } 
    streamAvg(arr, arr_size); // Call the function to calculate streaming averages
    return 0; // End of the main function
}

Sample Output:

Elements in array are: 10.000000  20.000000  30.000000  40.000000  50.000000  60.000000  70.000000  80.000000  90.000000  100.000000  
Average of 1 numbers is 10.000000 

Average of 2 numbers is 15.000000 

Average of 3 numbers is 20.000000 

Average of 4 numbers is 25.000000 

Average of 5 numbers is 30.000000 

Average of 6 numbers is 35.000000 

Average of 7 numbers is 40.000000 

Average of 8 numbers is 45.000000 

Average of 9 numbers is 50.000000 

Average of 10 numbers is 55.000000 

Flowchart:

For more Practice: Solve these Related Problems:

• Write a C program to compute a running average of numbers input as a stream, updating after each new number.
• Write a C program to calculate cumulative averages and display the result after each addition using incremental formulas.
• Write a C program to read numbers from an array and print the average after processing each element sequentially.
• Write a C program to maintain a dynamic average with each new input without storing all previous numbers.

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