math.h里面提供了很多常用的數(shù)學(xué)函數(shù)寄猩，這里記錄一下常用的晃洒。
extern float floorf(float);
extern double floor(double);
extern long double floorl(long double);
floor
extern float ceilf(float);
extern double ceil(double);
extern long double ceill(long double);
ceil
extern float roundf(float);
extern double round(double);
extern long double roundl(long double);
