Select sort.

select_sort.c

#include <stdio.h>

#define swap(x, y) { int tmp = x; x = y; y = tmp; }

void select_sort(int n, int* l) {
  for(int i = 0; i < n; ++i) {
    int min = i;
    for(int j = i; j < n; ++j)
      if(l[j] < l[min]) min = j;
    swap(l[i], l[min]);
  }
}

#define test(...) { \
  int l[] = { __VA_ARGS__ };        \
  int n = sizeof(l) / sizeof(int);  \
  select_sort(n, l);                \
  for(int i = 0; i < n; ++i)        \
    printf("%d ", l[i]);            \
  putchar('\n');                    \
}

int main(void) {
  test(1, 2, 6, 9, 8, 3, 10, 7, 5, 4);
  test(7, 10, 2, 9, 1, 8, 5, 4, 6, 3);
  test(5, 10, 3, 8, 6, 4, 7, 1, 9, 2);
  test(3, 8, 10, 1, 9, 5, 7, 6, 2, 4);
  test(2, 1, 8, 5, 4, 10, 7, 6, 9, 3);
  test(6, 8, 3, 9, 5, 7, 2, 1, 10, 4);
  test(1, 2, 6, 5, 9, 4, 8, 3, 7, 10);
  test(1, 2, 8, 6, 5, 7, 10, 4, 3, 9);
  test(3, 5, 4, 6, 8, 2, 10, 9, 7, 1);
  test(9, 4, 3, 6, 1, 7, 2, 10, 8, 5);
  return 0;
}