A naive implementation of Insertion Sort in C.

insertion-sort.c

/*
 * a naive implementation of Insertion Sort in C.
 */

void
insertion_sort(int *array, int array_len)
{
  int i;

  for (i = 1; i < array_len; i++) {
    int value = array[i];
    int j = i - 1;
    int done = 0;

    for (;;) {
      if (array[j] > value) {
        array[j + 1] = array[j];
        j--;
        if (j < 0) {
          done = 1;
        }
      } else {
        done = 1;
      }

      if (done) break;
    }

    array[j + 1] = value;
  }
}


/*
 * let's try it...
 */

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

int
main()
{
  int array_len = 1000;
  int array[array_len];
  int i;

  for (i = 0; i < array_len; i++) {
    array[i] = random() / (RAND_MAX / 10000);
  }

  insertion_sort(array, array_len);

  for (i = 0; i < array_len; i++) {
    printf ("%d\n", array[i]);
  }

  return 0;
}