C Exercises: Calculate the average or median

C Callback function: Exercise-6 with Solution

Write a program in C program to calculate the average or median of an array of integers using a callback function to perform the calculation.

Sample Solution:

C Code:

#include <stdio.h>

#include <stdlib.h>
 // Function to calculate the average of an array
double calculate_average(int arr[], int n) {
  int sum = 0;
  for (int i = 0; i < n; i++) {
    sum += arr[i];
  }
  return (double) sum / n;
}
// Comparison function for sorting the array
int compare_ints(const void * a,
  const void * b) {
  int int_a = * ((int * ) a);
  int int_b = * ((int * ) b);
  return int_a - int_b;
}

// Function to calculate the median of an array
double calculate_median(int arr[], int n) {
  // Sort the array in ascending order
  qsort(arr, n, sizeof(int), compare_ints);

  // Calculate the median
  double median;
  if (n % 2 == 0) {
    median = (double)(arr[n / 2] + arr[n / 2 - 1]) / 2;
  } else {
    median = arr[n / 2];
  }
  return median;
}

// Function to calculate the average or median of an array
double calculate(int arr[], int n, double( * operation)(int arr[], int n)) {
  return operation(arr, n);
}
int main() {
  int arr[11] = {
    2,
    5,
    4,
    7,
    1,
    8,
    4,
    6,
    5,
    9,
    10
  };
  int n = sizeof(arr) / sizeof(arr[0]);
  printf("Original array elements: ");
  for (size_t i = 0; i < n; i++) {
    printf("%d ", arr[i]);
  }
  printf("\n");
  printf("\nSelect an option:\n");
  printf("1. Calculate average of the said array elements:\n");
  printf("2. Calculate median of the said array elements:\n");
  int option;
  scanf("%d", & option);
  double result;
  switch (option) {
  case 1:
    result = calculate(arr, n, calculate_average);
    printf("Average: %f", result);
    break;
  case 2:
    result = calculate(arr, n, calculate_median);
    printf("Median: %f", result);
    break;
  default:
    printf("Invalid option");
    break;
  }

  return 0;
}

Sample Output:

Original array elements: 2 5 4 7 1 8 4 6 5 9 10

Select an option:
1. Calculate average of the said array elements:
2. Calculate median of the said array elements:
1
Average: 5.545455
--------------------------------
Original array elements: 2 5 4 7 1 8 4 6 5 9 10

Select an option:
1. Calculate average of the said array elements:
2. Calculate median of the said array elements:
2
Median: 5.000000

Explanation:

In the above program, we declare two functions to perform the calculations: a) calculate_average() function to calculate the average of an array. b) calculate_median() function to calculate the median of an array. We also define a comparison function compare_ints() that is used by qsort() to sort the array in ascending order.

We then define a function calculate() that takes three arguments the array, the number of elements in the array, and a callback function ‘operation’. This function calls the ‘operation’ function to perform the calculation on the array.

In the main() function, we first define an array of integers and the number of elements in the array. Then, we ask the user to select an option to either calculate the average or median of the array. Depending on the user's choice, we call the calculate() function with the appropriate callback function (calculate_average() or calculate_median()). Finally, printf() function print the result to the console.

Flowchart:

C Programming Code Editor:

Previous: Convert a string to uppercase or lowercase.
Next: Remove all whitespace from a string.