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Index › Programming Questions & Help › Syntax Questions › char as Index, Index starting with 1 - possible
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char as Index, Index starting with 1 - possible? (Read 760 times)
Chrisir
char as Index, Index starting with 1 - possible?
Mar 27th, 2010, 3:07am  
Hello all,

can I have

 String[][] Buffer = new String[8][8];

and tell it to go only from

String['A' to 'H'][ 1 to 8 ];
?

This is asking:
Can I use a char or string as index?
And can I start elsewhere than 0 (here 1)
and can I mix char and int.

Or is is bad style?

Aiming at a game of chess.

Thank you!

Chrisir
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PhiLho 
Re: char as Index, Index starting with 1 - possible?
Reply #1 - Mar 27th, 2010, 10:19am  
"Can I use a char or string as index? "
No. (But there is HashMap, not useful in your case.)

"And can I start elsewhere than 0 (here 1) "
No, but you can declare an array of 9 elements and just ignore the first.

"can I mix char and int"
Not sure what you mean by that, but for information a char is a number in Java.

"Aiming at a game of chess."
You can map 'A' to 1, 'B' to 2, eg. with something like:
int pos = letter - 'A' + 1; // letter is a char
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Chrisir
Re: char as Index, Index starting with 1 - possible?
Reply #2 - Mar 27th, 2010, 10:33am  
Somehow, I knew it would be you how anwers that...   Wink

You are just somebody who likes ambitious tiny questions...  Wink

Thank you!
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Chrisir
Re: char as Index, Index starting with 1 - possible?
Reply #3 - Mar 27th, 2010, 2:29pm  

I posted the small chess-thing.

The pciking is only reliable with OPENGL.

http://www.openprocessing.org/visuals/?visualID=8530

Chrisir    Wink  

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Lie Ryan
Re: char as Index, Index starting with 1 - possible?
Reply #4 - Mar 27th, 2010, 5:22pm  
Chrisir wrote on Mar 27th, 2010, 3:07am:
Hello all,
String['A' to 'H'][ 1 to 8 ];


You can't use a string to index an array; and you can use a char (which is a number) and translate char 'A' to zero by "letter - 'A' + 1" trick; however, better yet, you can declare some constants:

// or use char to save a tad bit of space
final int A = 0, B = 1, C = 2, D = 3, E = 4, F = 5, G = 6, H = 7;

and access your array like:
a = Buffer[A][1];
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