#include <stdio.h>
int main(){
int pid=fork();// fork a child
if(pid) {// PARENT
printf ("PARENT %d CHILD=%d\n",getpid(),pid);
//sleep(1);	// sleep 1 second ==> let child run next
printf ( "PARENT%d EXIT\n",getpid());
}
else{
// child
printf ("child %d start my parent=%d\n",getpid(),getppid());
sleep(2);	// sleep 2 seconds => let parent die first
printf ("child %d exit my parent=%d\n",getpid(),getppid());
}
return 0;
}