#include <stdio.h>
#include <unistd.h>

int main(int argc, char **argv)
{
  printf("--beginning of program\n");

  int counter = 0;
  pid_t pid = fork();

  if (pid == 0)
  {
    // child process
    counter++;
    printf("child process: counter=%d\n", counter);
  }
  else if (pid > 0)
  {
    // parent process
    counter++;
    printf("parent process: counter=%d\n", counter);
    wait(pid);
  }else{
    printf("fork() failed!\n");
  }

  printf("--[PID%d] end of program. count =%d--\n", getpid(), counter);
  return 0;
}