Writing a GamesCrafters Game in C

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Writing a GamesCrafters Game in C

• Monday, Sept. 22, 2003
• Judy Chen

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What well cover today

• Quick introduction to C
• Hash Functions
• Sample game (Snake)

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C versus Java

• Local variables have to be at the top
• No Boolean type
• Structures
• / /
• printf(Foo is d and bar is f\n, 5, 3.5)
• for loops syntax
• variables arent initialized to anything

• anywhere
• Classes
• / ... / or //
• System.out.print

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Arrays

• C syntax for declaring an array is slightly
  different
• int myarray5
• int yourarray 1, 2, 3, 4, 5
• Accessing stuff in arrays is the same
• yourarray2 ?
• yourarray2 3
• Be careful b/c array bounds arent checked!

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Pointers

• Pointers represent raw memory addresses.

y
x
int x, y
?
?
y
x
y 5
?
5
Note that x still hasnt been initialized.
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Pointers (contd)

• Use the operator to get the address of a
  variable.

y
x
x y
5

• Use the operator to dereference a pointer.

y
x
x 7
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GamesCrafters

• Download the gamesman package for Unix. As of
  right now, there is no version for Windows.
  http//www.cs.berkeley.edu/ddgarcia/research/game
  theory/current
• The GamesCrafters website has the 10-step
  tutorial for writing a game module.
• http//www.cs.berkeley.edu/ddgarcia/software/gam
  esman

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Hash Functions

• A hash function takes your board position and
  converts it into a number.
• Each board position will have a unique number
  that it is hashed into.
• Youll need a hash function and an unhash
  function, which will take a number and give you
  the board position.

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Hashing Tic Tac Toe

• Ex Tic Tac Toe
• 0 for a blank square
• 1 for an X
• 2 for an O

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The Makefile

• There are 4 places where you need to add your
  game.
• Pick one of the current games (i.e. TTT) and
  every time you see that game, copy and paste it
  and change TTT to your game.

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The Makefile change 1

• TTT_EXE (BINDIR)/mttt
• TTT_OBJ mttt.o
• TTT_SO (LIBDIR)/libmttt.so

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The Makefile change 2

• text_all 1210_EXE TTT_EXE ...
• so_all 1210_SO TTT_SO ...

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The Makefile change 3

• TTT_OBJ SOLVER_INCLUDE
• TTT_EXE TTT_OBJ ...
• TTT_SO TTT_OBJ ...

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The Makefile change 4

• At the very end of the makefile...
• clean
• rm f 1210_EXE 1210_OBJ ...
• minimal
• rm f 1210_OBJ TTT_OBJ ...

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Compiling and running

• Log on to rhombus.cs (the most lenient compiler)
• Add your mgame.c code the gamesman/src directory
• gt cd gamesman/src
• gt make ?to compile
• gt cd ../bin
• gt ./mgame ?to execute

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Functions youll have to write

• GameSpecificMenu (maybe.. if you want to add
  Variants)
• GetInitialPosition
• DoMove
• Primitive
• PrintPosition
• GenerateMoves
• Hash and Unhash

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Questions?