preprocessor

Why does the following line of code generate error as " pasting / and / doesnot generate a valid preprocessing token"? Can someone please help



#define comment /##/
int main()
{
comment printf("hello");
return 0;
}

 

I know that Sir this question deals with pasting / and / which surely forms a single line comment

 

Its a preprocessor token pasting operator which joins its operands to make a valid token!!!

 

# this is symbol of preprocessor.
Ex- #include<stdio.h>
#include<conio.h>
void main()
{
{
}
getch()
}