C中的宏定义错误? [英] Macro definition error in C?

问题描述

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

它报错:期望的表达式在'/'标记之前.是因为我不能使用宏定义小数还是什么?

It complains error: expected expression before '/' token. Was is it bacause I can't use macro to define decimals or what?

推荐答案

删除分号:

#define SOUND_SPEED 0.034; 
                         ^

如果保留它，则生成的代码将如下所示:

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

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

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