Strange behaviour of macros C/C++

Question

I\'m using some macros, and observing some strange behaviour.

I\'ve defined PI as a constant, and then used it in macros to convert degrees to radians and radians to

Answer 1

Also good practice: Add brackets around all your parameters:

#define radians(deg)  ((deg) * PI / 180)

because the expression you pass as parameter might include operators, too.

Or even better: Use (inline-) functions instead of macros, to avoid surprises with sideeffects when a parameter is evaluated multiple times like here:

#define sqr(x)  ((x) * (x))

The only disadvantage you get with inline functions: You can define them for one type, only (unless you use C++ templates)