M_PI flagged as undeclared identifier

Question

When I compile the code below, I got these error messages:

(Error  1   error C2065: \'M_PI\' : undeclared identifier 
2   IntelliSense: identifier \"M_PI\"          


        

Answer 1

M_PI is supported by GCC too, but you've to do some work to get it

#undef __STRICT_ANSI__
#include 

or if you don't like to pollute your source file, then do

g++ -U__STRICT_ANSI__