How about preprocessor usage in C....?

[keane]

Hi everyone,
i wanna kno bout the preprocessor usage in c... i m a beginner for this, so experts you can judge bout it.thank u

[JosAH]

Hi everyone,
i wanna kno bout the preprocessor usage in c... i m a beginner for this, so experts you can judge bout it.thank u

What do you want to know about it exactly? (don't say: "how it works" please).
A preprocessor defines macros and rewrites text in which macros are present
including optional parameters. Note that a macro under expansion (rewriting)
is not being expanded further to avoid recursive behaviour. The preprocessor
properly tokenizes a piece of text for the compiler.

kind regards,

Jos

[keane]

What do you want to know about it exactly? (don't say: "how it works" please).
A preprocessor defines macros and rewrites text in which macros are present
including optional parameters. Note that a macro under expansion (rewriting)
is not being expanded further to avoid recursive behaviour. The preprocessor
properly tokenizes a piece of text for the compiler.

kind regards,

Jos

Thank u, i dont need any technical explanation just i wanna kno bout where preprocessor would be more helpful... that means which kinda applications or programs.... Is it really a most effective topic

[JosAH]

Thank u, i dont need any technical explanation just i wanna kno bout where preprocessor would be more helpful... that means which kinda applications or programs.... Is it really a most effective topic

Well, basically using a preprocessor should improve readability of the code and
should help you in typing consistent code on a very basic level. You can define
macros that you can use throughout your code. e.g. the following (sloppy) macro
is a shorthand for the maximum value of two values x and y:

[code=c]
#define MAX(x, y) (((x)>(y))?(x): (y))
[/code]

... so instead of typing (or reading!) all those nasty brackets and magic expressions
you can simply do:

int max= MAX(a, b);

But note that this macro (as well as many macros) has a flaw, i.e. it evaluates
the value of the maximum twice and macros hide those facts. More modern
languages have other solutions instead of preprocessor macros for that.

kind regards,

Jos