what is # symbol in C?

[zweety]

what is the function of # symbol in C.
for eg:# include<stdio.h>.this statement is used for linking the i/p nd o/p fns in the pgm to the header file.is this # is the directive.somebody said to me that # is assembler directive.can anyone explain what an assembler directive is?

[JosAH]

what is the function of # symbol in C.
for eg:# include<stdio.h>.this statement is used for linking the i/p nd o/p fns in the pgm to the header file.is this # is the directive.somebody said to me that # is assembler directive.can anyone explain what an assembler directive is?

The '#' introduces a so called 'pp-token', i.e. a 'preprocessor token'. It has nothing
to do with assembly or whatever. Within a preprocessor directive this character
may be the catenation operator or the stringize operator. It's all preprocessor
stuff which by itself has nothing to do with the C(++) language itself.

kind regards,

Jos

ps. what is "i/p nd o/p fns"?

[scruggsy]

The '#' introduces a so called 'pp-token', i.e. a 'preprocessor token'. It has nothing
to do with assembly or whatever. Within a preprocessor directive this character
may be the catenation operator or the stringize operator. It's all preprocessor
stuff which by itself has nothing to do with the C(++) language itself.

kind regards,

Jos

ps. what is "i/p nd o/p fns"?

I think that translates to "i/o functions".

To clarify a little bit on what Jos said, preprocessor directives are a way of communicating with the compiler while it's building your code. Like telling it what other source files to include, or defining macros (text substitution), or telling it to ignore parts of the code under certain conditions. They are not part of the C++ language.

[tburger]

Outside of indicating which source files / libraries to include, the "#" character can also be used to define a "global constant"...

example:

#define PI 3.145

Anywhere you use "PI" in your code, the compiler will replace it with the value 3.145.

It's another way to set a constant in C. It becomes quite handy when "PI" comes up in your code many times. Instead of having to find and replace 10 "PI" values, all you have to do is change the #define value and the compiler will do it for you...

Enjoy

Tom

[epyk]

ive know # as a compiler directive, it allows you to use the compiler to edit, add or select code during compile time. you can prolly find documentation on whatever compiler you are using