Mimic the dealer

Mimic the dealer

Difficulty: 08/100

This example implements a “mimic-the-dealer strategy,” i.e. hits if the hand totals less than seventeen and stands on eighteen or more. The player—as the dealer—stands on hard seventeen but hits on soft seventeen.

This time, the configuration file blackjack.conf is used. If a file with this name exists in the directory where blackjack is executed, it is read and parsed. The options should be fairly self descriptive. See the [configuration file] section of the manual for a detailed explanation of the variables and values that can be entered. In particular, we ask to play one hundred thousand hands at a six-deck game where the dealer hits soft seventeens. The random seed is set to a fixed value so each execution will lead to the very same sequence of cards. In this case, the configuration file reads:

h17 = true
hands = 1e5
rng_seed = 12345

The player this time is implemented as an AWK script, whose input should be read from a piped name d2p (i.e. dealer to player) and whose output should be written to p2. To run the game, execute blackjack in one terminal making sure the current directory is where the blackjack.conf file exists.

$ blackjack > d2p < p2d 

In another terminal run the player

$ ./mimic-the-dealer.awk < d2p > p2d

Both dealer and player may be run in the same terminal putting the first one on the background:

rm -f d2p p2d; mkfifo d2p p2d
./mimic-the-dealer.awk < d2p > p2d &
blackjack > d2p < p2d 

The report should always be the same because the random number generator seed is fixed:

result: "(-5.7 ± 0.9) %"
mean: -0.057095
error: 0.0092763
hands: 100000
bankroll: -5709.5
bustsPlayer: 0.27214
bustsDealer: 0.19076
wins: 0.41149
pushes: 0.09727
losses: 0.49124

Exercise: modify the player and the configuration file so both the dealer and the player may stand on soft seventeen. Analyze the four combinations (player h17 - dealer h17, player h17 - dealer s17, player s17 - dealer h17, player s17 - dealer s17)