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Version 1 update.
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@krisluczka
krisluczka committed Jul 16, 2024
1 parent 3e04f9b commit f0d8cd7
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191 changes: 12 additions & 179 deletions Blackjack probabilistic calculator/Blackjack probabilistic calculator.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -47,167 +47,7 @@ static inline void cls() {
#endif
}

/*
Simulate one card position
*/
void static_simulation( uint_fast64_t amount ) {
cls();
random_device dev;
uniform_int_distribution<int> random_card( card_2, card_A );

cout << " <----------------------------------------------------------> \n\n";
string input;
cards player_card;
cards dealer_card;

bool dealer_ace( false ), player_ace( false );
uint_fast8_t player_score( 0 ), low_player_score( 21 );
uint_fast8_t dealer_score( 0 ), low_dealer_score( 21 );
uint_fast8_t rc;

uint_fast64_t wins( 0 );
uint_fast64_t daws( 0 );
uint_fast64_t dws[5] = { 0,0,0,0,0 };

// inputs
cout << " 2 3 4 5 6 7 8 9 D J Q K A ( to stop giving cards type X ) \n";
for ( uint_fast8_t i( 0 ); i < 11; ++i ) {
cout << " Player's card >> "; cin >> input;

if ( input == "x" || input == "X" )
break;

player_card = parse_card( input );

// ace handling
if ( player_card == card_A ) {
if ( player_ace )
player_score += 1;
else
player_score += 11;

player_ace = true;
}

// not ace handling
else
player_score += player_card;

// lower ace score
low_player_score = player_score - 10;
}
cout << " Dealer's card >> "; cin >> input;
dealer_card = parse_card( input );

if ( player_score > 21 ) {
// if overflowed use the ace
if ( player_ace )
player_score = low_player_score;

// tactic didn't work because of player's overflow
else
return;
}

// the lower score can also be overflowed
if ( player_score > 21 )
return;

// THE SIMULATION
for ( uint_fast64_t i( 0 ); i < amount; ++i ) {
// setup
dealer_score = dealer_card;

// dealer starting ace test
dealer_ace = (dealer_card == card_A);
if ( dealer_ace )
low_dealer_score = 1;
else
low_dealer_score = 21;

// simulating dealer's hand
while ( dealer_score < 17 || (dealer_ace && (low_dealer_score < 17)) ) {
rc = random_card( dev );

// handling aces
if ( rc == card_A ) {
if ( dealer_ace )
dealer_score += 1;
else
dealer_score += 11;

dealer_ace = true;
} else dealer_score += rc;

if ( dealer_ace )
low_dealer_score = dealer_score - 10;
}

if ( dealer_score > 21 ) {
// if overflowed use the ace
if ( dealer_ace )
dealer_score = low_dealer_score;

// tactic worked because of dealer's overflow
else {
++wins;
continue;
}
}

// the lower score can also be overflowed
if ( dealer_score > 21 ) {
++wins;
continue;
}

// tactic worked because of winning score
if ( player_score >= dealer_score ) {
++wins;
continue;
}

// womp womp tactic bad, let's save statistics
daws += dealer_score;
++dws[dealer_score - 17];
}

// winning percentage
long double percentage( (long double)(wins) / (long double)(amount) );

// the results
cout << "\n <-----> \n";
cout << " The calculated decision >> \n";

if ( wins >= amount / 2 ) {
cout << " - " << percentage * 100 << " % > STOP <\n";
cout << " - " << (1 - percentage) * 100 << " % take\n";
} else {
cout << " - " << percentage * 100 << " % stop\n";
cout << " - " << (1 - percentage) * 100 << " % > TAKE <\n";
}
cout << " <-----> \n\n";

// dealer's average winning score
cout << " Dealer's won matches statistics\n";
if ( wins != amount ) {
cout << " Average winning score >> " << (long double)(daws) / (long double)(amount - wins) << "\n\n";

for ( uint_fast8_t i( 0 ); i < 5; ++i )
if ( dws[i] != 0 )
cout << " Winning score " << i + 17 << " occured " << (long double)(dws[i]) / (long double)(amount - wins) * 100 << " % of times\n";
}

cout << "\n <----------------------------------------------------------> \n\n";
cout << " Press any key to start new simulation.\n";
cin.ignore();
cin.get();
}

/*
Dynamically simulate given position (add cards after evalution)
*/
void dynamic_simulation( uint_fast64_t amount ) {
void simulation( uint_fast64_t amount ) {
cls();
random_device dev;
uniform_int_distribution<int> random_card( card_2, card_A );
Expand Down Expand Up @@ -253,7 +93,7 @@ void dynamic_simulation( uint_fast64_t amount ) {
// lower ace score
low_player_score = player_score - 10;
}
cout << " Dealer's card >> "; cin >> input;
cout << "\n Dealer's card >> "; cin >> input;
dealer_card = parse_card( input );

if ( player_score > 21 ) {
Expand Down Expand Up @@ -338,11 +178,11 @@ void dynamic_simulation( uint_fast64_t amount ) {
cout << " The calculated decision >> \n";

if ( wins >= amount / 2 ) {
cout << " - " << percentage * 100 << " % > STOP <\n";
cout << " - " << (1 - percentage) * 100 << " % take\n";
cout << " - " << percentage * 100 << " % > STAND <\n";
cout << " - " << (1 - percentage) * 100 << " % hit\n";
} else {
cout << " - " << percentage * 100 << " % stop\n";
cout << " - " << (1 - percentage) * 100 << " % > TAKE <\n";
cout << " - " << percentage * 100 << " % stand\n";
cout << " - " << (1 - percentage) * 100 << " % > HIT <\n";
}
cout << " <-----> \n\n";

Expand Down Expand Up @@ -423,7 +263,7 @@ void dynamic_simulation( uint_fast64_t amount ) {
// cout << " You can search by typing player score.\n";
// cout << " Type X to reset searching. \n\n\n";
//
// cout << " | Player score | Dealer score | Take % | Stop % |\n\n";
// cout << " | Player score | Dealer score | hit % | stand % |\n\n";
//
// for ( uint_fast64_t i( 0 ); i < tokens.size(); i += 4 ) {
// if ( searching )
Expand All @@ -450,7 +290,7 @@ void dynamic_simulation( uint_fast64_t amount ) {
// if ( (18 - tokens[i + 1]->size()) % 2 ) cout << " ";
// cout << "|";
//
// // take chance
// // HIT chance
// for ( uint_fast8_t n( 0 ); n < (12 - tokens[i + 2]->size()) / 2; ++n )
// cout << " ";
// cout << *tokens[i + 2];
Expand Down Expand Up @@ -493,7 +333,7 @@ int main() {
cout << " /--------------------------------------\\ \n";
cout << " | |\n";
cout << " | Blackjack probabilistic |\n";
cout << " | calculator ( v1.0 ) |\n";
cout << " | calculator version 1 |\n";
cout << " | |\n";
cout << " | by Krzysztof Luczka |\n";
cout << " | |\n";
Expand All @@ -508,17 +348,10 @@ int main() {
cout << " 1. Dynamic mode\n";
cout << " Type player cards on the fly\n";
cout << " without additional statistics.\n";
cout << " 2. Static mode\n";
cout << " Type player cards and wait for\n";
cout << " the full evaluation.\n\n";
/*cout << " 3. Rainbow tables\n";
/*cout << " 2. Rainbow tables\n";
cout << " Table with precalculated stats.\n\n";*/
cout << " >> "; cin >> input;

if ( input == "2" ) while ( 1 )
static_simulation( 10000000 );
/*else if ( input == "3" )
rainbow_table();*/
else while ( 1 )
dynamic_simulation( 1000000 );

simulation( 1000000 );
}
2 changes: 1 addition & 1 deletion LICENSE.txt
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
MIT License

Copyright (c) [year] [fullname]
Copyright (c) 2024 Krzysztof Łuczka

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
Expand Down
8 changes: 7 additions & 1 deletion README.md
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@@ -1 +1,7 @@
# Blackjack probabilistic calculator
# Blackjack probabilistic calculator
A simple calculator that evaluates the chances of winning a given position in blackjack. Due to the fact that _double down_, _split_ and _insurance_ are purely gambling decisions based on one's own sense of luck or they come down to the basic _hit_ and _stand_, the project calculates the probability of winning if we _stand_.
## The method
Calculator simulates through a given number (hardcoded milion) of random positions to reveal what percentage of games where we _stand_ with given set of cards we won.
## Result interpretation
Calculating your chances of winning after taking a card is yet to be added. Regarding version 1.0, the result only reveal the winning chances when we _stand_. Even though it is far accurate, the game is about maximizing chances - thus the new version will include _hit_ winning chances.
For example, when we have **King** and **Queen** (20 points) and the dealer has **Jack** (10 points), the percentage of winning after _stand_ decision will be around 92% which is a really good approximation - we should _stand_. But sometimes there might be a situation where we win 55% of times while _standing_. We don't know the statistic of winning while _hitting_, but it might be a little bit higher, for example 65%, thus we should _hit_ instead of _standing_.

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