CODEWITHSUNDEEP
ctypesartificial-intelligence
user2030118
user2030118

Reputation: 155

Signed or Unsigned long for 8x8 game board in c

I am programming a Reversi game in C, and i am new to the language (coming from java),and also have never programmed a game with 8x8 board before. I want to use bit Boards to represent the game board for both white and black players (one 64 bit word for each), and i wonder if i should use an Unsigned long long for that purpose.

From what I know, an Unsigned Type is a one that doesn't use the leftMost bit as a sign indicator (0 for positive and 1 for negative), I also know that java for example,support only signed Types. but in my case, I would need to use the left most bit as a valid square for the board. Does it matter if i use a signed type or unsigned type for that??

for example, if i place a white piece on the last square of the white bitBoard (the left most bit) and the number will become negative, is it ok?

Upvotes: 1

Views: 238

Answers (1)

meaning-matters
meaning-matters

Reputation: 22946

Yes, if you're doing things with bits, you'd better use unsigned.

Note that unsigned long long is guaranteed to be at least 64 bits, by the C standard.

Have a look at bit-fields, very handy in your case; saves you bit-fiddling with &, |, ^, ...

But here's an idea:

#include <stdint.h>  // Thanks @DoxyLover
typedef struct
{
    uint8_t a : 1;
    uint8_t b : 1;
    uint8_t c : 1;
    uint8_t d : 1;
    uint8_t e : 1;
    uint8_t f : 1;
    uint8_t g : 1;
    uint8_t h : 1;
} BoardRow;

typedef struct
{
    BoardRow r1;
    BoardRow r2;
    BoardRow r3;
    BoardRow r4;
    BoardRow r5;
    BoardRow r6;
    BoardRow r7;
    BoardRow r8;
} Board;

void someFunction(void)
{
    Board board;

    board.r5.d = 1;
    ...

    // You can save these board in uint64_t if you like.
    uint64_t savedBoard = (uint64_t)board;
    ...
}

Upvotes: 2

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