C Exercises: Average of a variable number

C Variadic function: Exercise-6 with Solution

Write a C program to find the average of a variable number of doubles passed as arguments to a function using variadic functions.

Sample Solution:

C Code:

#include <stdio.h>

#include <stdarg.h>

double calculate_average(int num, ...) {
  double sum = 0;
  int i;
  va_list arguments;
  va_start(arguments, num);
  for (i = 0; i < num; i++) {
    sum += va_arg(arguments, double);
  }
  va_end(arguments);
  return sum / num;
}
int main() {
  double avg = calculate_average(4, 10.2, 20.3, 30.4, 40.5);
  printf("The average is: %f\n", avg);
  return 0;
}

Sample Output:

The average is: 25.350000

Explanation:

In the above program, we define a function called "calculate_average()" that accepts a variable number of arguments. It starts by initializing a va_list object called arguments with va_start. This takes the va_list object and the number of arguments passed. We then loop through the arguments, adding them to a running total in the sum variable. This is done using the va_arg function, which takes the va_list object and the type of argument we want to retrieve. Finally, we use va_end to free the va_list object and return the average of the numbers.

In the main function, we call the “calculate_average()” function with four arguments, and print out the result. This program can be used to find the average of any number of doubles passed as arguments.

Flowchart:

C Programming Code Editor:

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