/*
 * This code is from "Algorithms in C, Third Edition,"
 * by Robert Sedgewick, Addison Wesley Longman, 1998.
 */
#include <stdlib.h>
main(int argc, char *argv[])
  { long int i, j, N = atoi(argv[1]);
    int *a = malloc(N*sizeof(int));
    if (a == NULL) 
      { printf("Insufficient memory.\n"); return; }
    ...