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Example to explain working (#25137)

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hariom Choudhary
2018-12-19 13:45:29 +05:30
committed by Manish Giri
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guide/english/c/macros/index.md
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@ -66,6 +66,15 @@ You get the equivalent of:
```C ```C
printf("Hello World!"); printf("Hello World!");
``` ```
An example to explain how code is replaced by macros
```c
#define add(a,b) a+b
```
Now calling :
```c
int x = 2*add(3,5)*4;
```
Here, the value of x will be 26 because the expression will become 2*3+5*4 which evaluates to give 26. Sometimes we think that the macro will give us 3+5 i.e. 8 and the expression will become 2*8*4 but this is not the case. This shows how the code is replaced exactly.
#### Special Operators in Macros #### Special Operators in Macros
One can use the special operators # (stringize) and ## (concatenate) in macros for achieving unique functionality. One can use the special operators # (stringize) and ## (concatenate) in macros for achieving unique functionality.