there has to be a better way

dabigmooish · #1 15-May-2004, 00:40

Howdy I've got two functions that are almost exactly the same. The only difference is that one checks for uppercase letters the other does lowercase. I was just wondering if anyone could think of a more productive method of doing this?

Here's my code:

CPP / C++ / C Code:

int gamerules::CheckPiece(char alpha, int row, int player)
{

	gamesaveload g;
	int alphaNum;
	int returnValue = 0;


	switch(alpha)
	{
		case 'A':
		case 'a':
			alphaNum = 0;
		break;

		case 'B':
		case 'b':
			alphaNum = 1;
		break;

		case 'C':
		case 'c':
			alphaNum = 2;
		break;

		case 'D':
		case 'd':
			alphaNum = 3;
		break;

		case 'E':
		case 'e':
			alphaNum = 4;
		break;

		case 'F':
		case 'f':
			alphaNum = 5;
		break;

		case 'G':
		case 'g':
			alphaNum = 6;
		break;

		case 'H':
		case 'h':
			alphaNum = 7;
		break;
	}


	if(player == 1)
	{
		switch(g.board[alpha][row])
		{
			case 'r':
			case 'n':
			case 'b':
			case 'k':
			case 'q':
			case 'p':
				cout <<"I'm sorry that is not your piece.  Please select another.\n";
			break;
			
			default:
				returnValue = 1;
		}
	}
	else
	{
		switch(g.board[alpha][row])
		{
			case 'R':
			case 'N':
			case 'B':
			case 'K':
			case 'Q':
			case 'P':
				cout <<"I'm sorry that is not your piece.  Please select another. \n";
			break;
			
			default:
				returnValue = 1;
		}
	}

	return(returnValue);
}

and the other function:

CPP / C++ / C Code:

int gamerules::CheckMove(char alpha, int row, int player)
{
	gamesaveload g;
    int alphaNum;
    int returnValue = 0;


	switch(alpha)
	{
		case 'A':
		case 'a':
			alphaNum = 0;
		break;

		case 'B':
		case 'b':
			alphaNum = 1;
		break;

		case 'C':
		case 'c':
			alphaNum = 2;
		break;

		case 'D':
		case 'd':
			alphaNum = 3;
		break;

		case 'E':
		case 'e':
			alphaNum = 4;
		break;

		case 'F':
		case 'f':
			alphaNum = 5;
		break;

		case 'G':
		case 'g':
			alphaNum = 6;
		break;

		case 'H':
		case 'h':
			alphaNum = 7;
		break;
	}


	if(player == 1)
	{
		switch(g.board[alpha][row])
		{
			case 'R':
			case 'N':
			case 'B':
			case 'K':
			case 'Q':
			case 'P':
				cout <<"I'm sorry you can't move there.  Please move again.\n";
			break;
			
			default:
				returnValue = 1;
		}
	}
	else
	{
		switch(g.board[alpha][row])
		{
			case 'r':
			case 'n':
			case 'b':
			case 'k':
			case 'q':
			case 'p':
				cout <<"I'm sorry you can't move there.  Please move again. \n";
			break;
			
			default:
				returnValue = 1;
		}
	}

	return(returnValue);

}

machinated · #2 15-May-2004, 07:20

upper case characters are 65 - 90
lower case characters are 97 - 120

to convert from upper case to lower case: add 32
to convert form lower case to upper case: subract 32

CPP / C++ / C Code:

char ch = 'A';
ch+=32;
cout<<ch; //prints 'a'

dsmith · #3 15-May-2004, 07:48

I always use the functions tolower or toupper when I want to convert case. They are standard ansi C and they do checking to make sure that your can be converted to requested case. They are defined as:

CPP / C++ / C Code:

#include <ctype.h>

int toupper(int c);
int tolower(int c);

So that if have something like:

CPP / C++ / C Code:

char ch1 = 'a';
char ch2 = 'A';

printf("Uppercase of ch1=%c\n",toupper(ch1));
printf("Uppercase of ch2=%c\n",toupper(ch2));

That should print a capital A in both cases.

Cheers,
d

WaltP · #4 15-May-2004, 11:18

Remove the switch block and add another parameter:

CPP / C++ / C Code:

int gamerules::CheckPiece(char alpha, int row, int player, bool piece)
{
    gamesaveload g;
    int alphaNum;
    int returnValue = 0;

    alphaNum = toupper(alpha) - 'A'; // convert character to binary

    if (piece)    // boolean value TRUE if testing a piece, FALSE if testing a move
    {
	if(player == 1)
	{
		switch(g.board[alpha][row])
		{
			case 'r':
			case 'n':
			case 'b':
			case 'k':
			case 'q':
			case 'p':
				cout <<"I'm sorry that is not your piece.  Please select another.\n";
			break;
			
			default:
				returnValue = 1;
		}
	}
	else
	{
		switch(g.board[alpha][row])
		{
			case 'R':
			case 'N':
			case 'B':
			case 'K':
			case 'Q':
			case 'P':
				cout <<"I'm sorry that is not your piece.  Please select another. \n";
			break;
			
			default:
				returnValue = 1;
		}
	}
    }
    else
    {
        // add the other block here from CheckMove()
        // Then look again to see it you can combine more
    }
	return(returnValue);
}

(and don't use TABs, they format badly on forums, as you can see above)

aaroncohn · #5 15-May-2004, 11:31

Tabs also don't port well to other IDEs. I agree with dsmith, and that's what I would've said. Just convert the characters to the proper case.

dabigmooish · #6 16-May-2004, 20:00

thanks everyone for your help. I like the ideal of using a booleen but it really just puts both functions into one, not really improving the code any. I also think that there is a little missunderstanding as to what I'm trying to do. I've making a chess game. The board (which is q.board[][] in these functions) is made of charaters. White pieces are uppercase (R, N, B, K, Q, P) and black pieces are lowercase (r, n, b, k, q, p). What the first function - CheckPiece- does is make sure that player one is selecting to move his own piece, i.e. the uppercase letters and vice verse with player 2. The second function - CheckMove- checks to see if the player is moving his piece onto his own piece. The reason for the first switch statement is to turn the user input row into the actual matrix index. Let me explain

Here's what the board looks like when printed:

1 2 3 4 5 6 7 8
A R N B K Q B N R
B P P P P P P P P
C
D
E
F
G p p p p p p p p
H r n b k q b n r

The user is then asked to enter which piece he would like to move. A1 would be a white rook, H4 would be a black king, and so on. In the matrix A1 is actually 0,0 so the first switch takes the A and converts it to zero. That switch has to be there.

Max Payne · #7 16-May-2004, 20:32

Here is what I would do,find the ASCII numbers for each char and do some math on them..:

CPP / C++ / C Code:

int gamerules::CheckMove(char alpha, int row, int player)
{
  gamesaveload g;
    int alphaNum;
    int returnValue = 0;

//if alpha is in range (A-H)
if(alpha >=65 && alpha<=72)
     alphaNum=alpha-65;
//if alpha is in range (a-h)
else if(alpha >=97 && alpha<=104)
     alphaNum=alpha-97;
...
...
...
}

you can do the same on other functions..

WaltP · #8 16-May-2004, 23:31

Quote:

Originally Posted by dabigmooish

In the matrix A1 is actually 0,0 so the first switch takes the A and converts it to zero. That switch has to be there.

Really? If you type in A1, and the A goes into chr, doesn't chr - 'A' equal 0?
If chr has 'C', doesn't chr - 'A' equal 2?
If chr has 'G', doesn't chr - 'A' equal 6?

So what does the switch accomplish that chr - 'A' doesn't other than taking extra time and code space?

dabigmooish · #9 17-May-2004, 11:24

Quote:

Originally Posted by WaltP

Really? If you type in A1, and the A goes into chr, doesn't chr - 'A' equal 0?
If chr has 'C', doesn't chr - 'A' equal 2?
If chr has 'G', doesn't chr - 'A' equal 6?

So what does the switch accomplish that chr - 'A' doesn't other than taking extra time and code space?

my apologie's for misunderstanding your code. That is a much better way of doing it. Many, Many, Many thanks for all of your help

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