use Inline 'C';

use Benchmark 'cmpthese';

cmpthese( 1_000_000, { iterative_c => sub{guess_it_c(4999,1,10000)},
                       recursive_c => sub{guess_rec_c(4999,1,10000)},
                       iterative_p => sub{guess_it_p(4999,1,10000)},
                       recursive_p => sub{guess_rec_p(4999,1,10000)},});

sub guess_it_p {
    my ( $ans, $lower, $higher ) = @_;
    my $guess;
    while(1) {
        $guess = int(($lower + $higher)/2);
      last if $ans == $guess;
        if ( $guess > $ans ) {
            $higher = $guess -1;
        }
        else {
            $lower = $guess +1;
        }
    }
  return $guess;
}

sub guess_rec_p {
    my ( $ans, $lower, $higher ) = @_;
    my $guess = int(($lower + $higher)/2);
    if ($ans == $guess) {
        return $guess;
    }
    if ( $guess > $ans ) {
            guess_rec_p( $ans, $lower, $guess -1 );
    }
    else {
        guess_rec_p( $ans, $guess +1, $higher );
    }
}

__END__
__C__
int guess_it_c( int ans, int lower, int higher ) {
    int guess;
    for(;;) {
        guess = (int)((lower + higher)/2);
        if ( ans == guess ) break;
        if ( guess > ans )
            higher = guess -1;
        else
            lower = guess +1;
    }
  return guess;
}

int guess_rec_c( int ans, int lower, int higher ) {
    int guess;
    guess = (int)((lower + higher)/2);
    if (ans == guess) return guess;
    if ( guess > ans ) {
         guess_rec_c( ans, lower, guess -1 );
    }
    else {
        guess_rec_c( ans, guess +1, higher );
    }
}