Using Parentheses in Define Preprocessor Statements

Question

So I was wondering when is to use

 #define xxx (yyy)

vs

 #define xxx  yyy

My project includes a files tha

Answer 1

There is no difference in both. In first case XXX is replaced by yyy and by (yyy) is second case. The convention to use brackts is to avoid logical errors that may occur. For example you define addition function as:

#define f(N) N+N 
int a = f(5)*f(5)  

Expected value is 10*10 = 100 , but output is 35 because at compile time is becomes

int a = 5+5*5+5, so using operator preference rule, output changes.

So parenthesis avoid these type of errors.