From:	Jeramie DOT Hicks AT mail DOT utexas DOT edu (Jeramie Hicks)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Pointers to functions.
Date:	Mon, 08 Mar 1999 15:36:09 GMT
Organization:	The University of Texas at Austin, Austin, Texas
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On Sun, 7 Mar 1999 18:18:30 +0000, Dave Bird <dave AT xemu DOT demon DOT co DOT uk>
wrote:

> You might want to write a clever sort algorithm which can sort many
> different kinds of data.

That's a good example. Here's another: Suppose you want to choose one
function out of a hundred to handle a specific chunk of data, like an
opcode handler for a emulator. Instead of having a switch statement
that's hundreds of lines long, as in:

switch(opcode)
	{
	case OPCODE1: OpcodeHandler1();
	case OPCODE2: OpcodeHandler2();
	...
	case OPCODE254: OpcodeHandler254();
	case OPCODE255: OpcodeHandler255();
	};

You can have a clean, fast array of function pointers that is
initalized at the start. Then, when OPCODEX is read, the function at
the array index X is executed. Clean, fast, efficient. If you replace
the unused functions with a pointer to a default handler, it's even
better.

- Hicks

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