#include <stdio.h>

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

  int i;

  // print a welcome message
  printf("hello world!\n");

  // echo arguments if any
  if (argc == 1) {
    printf("no external argument for program %s\n", argv[0]);
  } else {
    printf("there are %d external argument for program %s\n", argc, argv[0]);
    for (i = 1; i < argc; i ++) {
      printf("argment %d -> %s\n", i, argv[i]);
    }
  }

  return 0;
}