Counting sort written in C

counting_sort_c.c

/* @(#)counting_sort_cool.c
 */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
/* #include "counting_sort.h"
 */

int main(int argc, char * argv[])
{

  int i, A_size;
  scanf("%d", &A_size);
  int *A = malloc(sizeof(int)*A_size);  
  for(i = 0; i < A_size; ++i)
    scanf("%d", &A[i]);

  int *B = malloc(sizeof(int)* A_size);
  int k = 0;

  clock_t t1 = clock();
  for(i = 0; i < A_size; ++i ){
    if( A[i] > k){
      k = A[i];
    }
  }

  int *C = malloc(sizeof(int)* k+1); /* +1 because of the zero */
  for(i = 0; i <= k; ++i){ C[i] = 0; }

  /* Count appearances */
  for(i = 0; i < A_size; ++i){
    C[A[i]]++;
  }

  /* Accumulate number of appearances */
  for(i = 1; i <= k; ++i){
    C[i] = C[i-1] + C[i];
  }

  /* Assign the number from A to a pos -1 in B (because of the zero in C)*/
  for(i = A_size-1; i >= 0 ; --i){
    B[ C[ A[i] ] -1 ]  = A[i];
    C[A[i]]--;
  }
  printf("Finished in %lf clocks per second\n", (double)(clock() - t1) / CLOCKS_PER_SEC);

  /* Print both arrays */
  puts("A");
  for(i = 0; i < A_size -1; i++){
    printf("%d, ", A[i]);
  }    printf("%d\n", A[A_size -1]);

  puts("B");
  for(i = 0; i < A_size -1; i++){
    printf("%d, ", B[i]);
  }    printf("%d\n", B[A_size -1]);

  free(A);
  free(B);
  free(C);

  return 0;
}