can somebody explain me what is macro in programming
with pratical examples and layman words

i think and i beleive that they are like the _time_ and the values that are self defined and also the things that are already defined in the libc and ready to be used in programming and without self defining them

am i right?

i think and i beleive that they are like the _time_ and the values that are self defined and also the things that are already defined in the libc and ready to be used in programming and without self defining them

am i right?

A quick search will turn up many useful links, including this Wikipedia article which looks very helpful.

A macro is essentially a short expression or marker which represents a larger block of code. When the macro is found by the language processor it is expanded into its full representation. This makes repetitive use of some code patterns less tedious and error prone, as noted in the above article.

Do you have a specific question about macro use? If so, it would be best to give a simple example of what you have in mind so that others here may provide a specific answer.

Please review the Site FAQ for guidance in asking well formed questions.

c programming macro
https://www.programiz.com/c-programm...-macros#macros

a macro are self defined things like values contained in libc or header files like _time_ or values of super globals don't know exactly whats their names like $_GET's values in php

No.

Some of those things may be macros, but that is not what macros "are". PHP's $_GET is not a macro.

Please read the linked article and perform your own search to try to find one that you can best understand easily. And read to understand, not so much for quick but incomplete answers.

Perhaps this GNU cpp documentation may be more helpful with specific examples.

macros are the only those who are used with #ifdef and #if

Originally, term 'macro-instruction' meant 'user-defined instruction' in Assembly, e.g.:

after a search of 2 weeks i have found that is that true

http://i.imgur.com/ytm2Azn.png

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I again ask you to please review the Site FAQ for guidance in posting your questions and general forum usage.

(Luckily, the OP has already found out what macros are, so no more answers are required.)

still didn't get it completly

[QUOTE= circumference = radius * 2 * pi;
The macro is called "circumference"

So, whenever you call the macro "circumference" the word is replaced with the whole contents of the text.

Exactly the same as in any text editor with macros.
[/QUOTE]

why would anyone substitue a variable with a value???

Please edit your post to make it more readable. Also please specify what programming language are you thinking of.

my language is c
can u tell me why would someone use macros in c for substiuate a variable with a value

Please edit your post#12 to make it more readable. Also please check if it has any #define in it -- if it is C-language and we are talking about macros, I would expect to see some #define-s.