Defining and calling macros in C Language
A macro is a segment of code which is replaced by the value of macro. Macro is defined by #define directive. There are two types of macros:
- Object-like Macros
- Function-like Macros
Object-like Macros
The object-like macro is an identifier that is replaced by value. It is widely used to represent numeric constants.
For example: #define PI 3.14
Here, MIN is the macro name.
to see the full example of object-like and function-like macros.
C Predefined Macros
ANSI C defines many predefined macros that can be used in c program.
No. | Macro | Description |
---|---|---|
1 | _DATE_ | represents current date in “MMM DD YYYY” format. |
2 | _TIME_ | represents current time in “HH:MM:SS” format. |
3 | _FILE_ | represents current file name. |
4 | _LINE_ | represents current line number. |
5 | _STDC_ | It is defined as 1 when compiler complies with the ANSI standard. |
#include
int main(){
printf("File :%s\n", __FILE__ );
printf("Date :%s\n", __DATE__ );
printf("Time :%s\n", __TIME__ );
printf("Line :%d\n", __LINE__ );
printf("STDC :%d\n", __STDC__ );
return 0;
}
Output:
File :simple.c Date :Dec 6 2015 Time :12:28:46 Line :6 STDC :1c language tutorial learn c language study c language