Arduino Bitwise Operators and advanced tricks | Hardware To Software

Let's say we are the owners of the Stratosphere casino at Las Vegas.
We want to know the status of all blackjack players located at stratosphere.
Stratosphere can have at max 6 tables of blackjack.
Each blackjack table can have at max 4 players simultaneously and each player can have at his hands at max 8 cards.
One could say that the each Stratosphere Blackjack player should have three integer values in order to determine his status.

unsigned int table_number; //The table number that he plays
unsigned int player_position; //His position at the table 0,1,2,3 (first,second,third or forth player)
unsigned int cards_number; //His amount of cards
Thinking even better the unsigned integers (two bytes) can become a byte (unsigned char) since a value 256 is way too high for table, position and card number.
So we could have defined our own player status struct in a BlackjackPlayerStatus.h header file like this :

struct BlackjackPlayerStatus {
  unsigned char table_number;    //byte is just an 'unsigned char'
  unsigned char player_position; //byte is just an 'unsigned char'
  unsigned char cards_number;    //byte is just an 'unsigned char'
};

Then we could have done :

BlackjackPlayerStatus JohnBlackjackStatus = {2,3,1};
//So John is located at the 2nd table 3rd position and has 1 card

In order to get these values we can do something like this :
unsigned char table = JohnBlackjackStatus.table_number;
unsigned char position = JohnBlackjackStatus.player_position;
unsigned char cards = JohnBlackjackStatus.cards_number;

Let's see with more details this example at arduino.

Here is the BlackjackPlayerStatus.h header file :

#ifndef BlackjackPlayerStatus_h
#define BlackjackPlayerStatus_h

struct BlackjackPlayerStatus {
  unsigned char table_number;    //byte is just an 'unsigned char'
  unsigned char player_position; //byte is just an 'unsigned char'
  unsigned char cards_number;    //byte is just an 'unsigned char'
};

#endif

Here is the StructExample.pde file which use the BlackjackPlayerStatus.h

#include "BlackjackPlayerStatus.h"

void PrintStatus(BlackjackPlayerStatus &PlayerStatus){
  Serial.print("Table : ");
  Serial.print(PlayerStatus.table_number,DEC);
  Serial.print(" ,Position : ");
  Serial.print(PlayerStatus.player_position,DEC);
  Serial.print(" ,Cards : ");
  Serial.println(PlayerStatus.cards_number,DEC);
}

void setup()                      // the set up part (runs only once)
{
  Serial.begin(9600);             // set up Serial library at 9600 bps  

  //Assign status at John Mary and Bob
  BlackjackPlayerStatus JohnBlackjackStatus = {2,3,1};
  //John Sits at table 2 at position 3with one card in hand
  BlackjackPlayerStatus MaryBlackjackStatus = {1,2,3};
  //Mary sits at table 1 at position 2 with three cards in hand
  BlackjackPlayerStatus BobBlackjackStatus = {5,4,3};
  //Bob sits at table 5 at position 4 with three cards in hand

  //Print status
  Serial.println("John's status : ");
  PrintStatus(JohnBlackjackStatus);
  Serial.println("Mary's status : ");
  PrintStatus(MaryBlackjackStatus);
  Serial.println("Bob's status : ");
  PrintStatus(BobBlackjackStatus);

  Serial.println("It is Bob's turn. Bob thinks ...");
  delay(3000);

  Serial.println("Bob decides to hit (take a card)");
  BobBlackjackStatus.cards_number = BobBlackjackStatus.cards_number + 1; 

  Serial.println("Bob's new status : ");
  PrintStatus(BobBlackjackStatus);

}

void loop()                       // The main loop (runs over and over again)
{
                                  // Do nothing...
}