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

Drop the semicolon:

#define SOUND_SPEED 0.034; 
                         ^

If you keep it the generated code will look like this:

distance = (double)(rtt*SOUND_SPEED;)/2;
                                   ^