C Exercises: Sort a variable number of integers

C Variadic function: Exercise-8 with Solution

Write a C program to sort a variable number of integers passed as arguments to a function using variadic functions.

Sample Solution:

C Code:

#include <stdio.h>

#include <stdarg.h>

void sort(int count, ...) {
  va_list args;
  va_start(args, count);

  // Put the numbers into an array
  int numbers[count];
  for (int i = 0; i < count; i++) {
    numbers[i] = va_arg(args, int);
  }
  // Sort the array using bubble sort
  for (int i = 0; i < count - 1; i++) {
    for (int j = 0; j < count - i - 1; j++) {
      if (numbers[j] > numbers[j + 1]) {
        int temp = numbers[j];
        numbers[j] = numbers[j + 1];
        numbers[j + 1] = temp;
      }
    }
  }
  // Print the sorted array
  for (int i = 0; i < count; i++) {
    printf("%d ", numbers[i]);
  }
  printf("\n");
  va_end(args);
}

int main() {
  sort(5, 9, 3, 7, 1, 5);
  sort(3, -2, 1, 0);
  return 0;
}

Sample Output:

1 3 5 7 9
-2 0 1

Explanation:

In this program, we utilize the va_list, va_start, va_arg, and va_end macros from the <stdarg.h> header file to handle variable arguments. We first call va_start to initialize args to point to the first argument after counting. We then use va_arg to get each integer argument and put it into an array. We sort the array by a simple bubble sort algorithm, and then print the sorted array. Finally, we use va_end to clean up after ourselves.

When we call the sort function, we first pass in the number of integers we're sorting, followed by the integers themselves.

Flowchart:

C Programming Code Editor:

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous: Implement the printf() function.