The next step is to make the server give the clients a hint whether the guessed number is greater or less than the secret number.
In the file game.erl, take a look at the game_loop_v3/2 function.
You must add code to game_loop_v3/2 so that the tuples {reply, {wrong, N, gt}}
and {reply, {wrong, N, lt}} are sent as replies when the guess N is greater
respectively smaller than the secret number.
Hint
Guards can be added to receive patterns similar to guards added to patterns in a case expression.
Until now, the players made guesses by picking a random number between Min and
Max. Since the server now tells a player if the guessed number was to large or
to small a player should use this information in order to increase the
probability of guessing the right number.
You must make changes in player_loop/5 so that a player takes advantage of the
added information about an incorrect guesses.
Hint
How can the interval [Min, Max] used by a player to make a random guess be
reduced based on the reply from the server?
Compile the updated module from the Erlang shell.
17> c(game).
{ok, game}
18>You might still get a few warnings.
Let’s try the new version of the server using a larger interval for the secret number.
18> S3 = game:test(v3, 1, 100, 2).
<0.289.0>
P1 [1 , 100] X > 51
P2 [1 , 100] X > 48
P1 [52 , 100] X > 54
P1 [55 , 100] X < 82
P2 [49 , 100] X < 58
P2 [49 , 57] X > 50
P1 [55 , 81] X < 80
P2 [51 , 57] X > 53
P1 [55 , 79] X < 74
P2 [54 , 57] X > 56
P1 [55 , 73] X < 73
P2 [57 , 57] X =:= 57 (6 guesses, PID = <0.291.0>)
P1 [55 , 72] X < 64
P1 [55 , 63] X < 63
P1 [55 , 62] X > 56
P1 [57 , 62] X < 61
P1 [57 , 60] X < 60
P1 [57 , 59] X < 58
P1 [57 , 57] X =:= 57 (13 guesses, PID = <0.290.0>)
19> We can use stats/2 to get the value of the server statistics.
19> game:stats(S3).
{stats,2,17}
20> Despite a large initial interval both players was able to find the secret number much faster than with the previous version of the game server.