Danger in using nested comments for quickly (de)activating code blocks in C++

Question

I'm currently using nested comments to quickly activate/deactivate code during testing, the way I'm doing it is like this :

//* First Case, Activated
DoSomething();
/**/

/* Second Case, De-Activated
DoSomethingElse();
/**/

I can activate, deactivate the code blocks by simply adding or deleting a '/'.

The compiler warns me about this, as nested comments are bad, but in reality, is it dangerous to use these comments?

Answer 1

This is how people normally do this:

#if 0
//...
#endif

or

#define TESTWITH

#ifdef TESTWITH
//..
#endif