int match(char *s1, char *s2) {
  while( *s1 != '\0' && *s2 != '\0' && *s1 == *s2 ){
    s1++; s2++;
  }
  return( *s1 - *s2 );
}

void welcome() { printf("Welcome to the Machine!\n"); exit(0); }
void goodbye() { printf("Invalid identity, exiting!\n"); exit(1); }

main(){
  char name[8];
  char pw[8]; 

  printf("login: "); 
  get_line(name);
  printf("password: "); 
  get_line(pw);

  if(match(name, pw) == 0)
    welcome();
  else
    goodbye();
}