Macro definition error in C?

Question

#define SOUND_SPEED 0.034;    
int rtt; //round trip time in microsecond
double distance;
distance = (double)(rtt*SOUND_SPEED)/2;

It complains erro

Answer 1

You're using C, but you're trying to use a C++ style // comment. Depending on your compiler, that may not be allowed.

Edit: In fact, gcc -c89 -ansi gives that exact error message for a // comment and a totally different one for the extraneous ; in the define.