答案:空
A. *
B. !=
C. +
D. =
A. double fun(double f1, double f2){ }
B. double fun(double f1; double f2){ }
C. double fun(double f1, double f2); { }
D. double fun(double f1, f2){ }
A. printf
B. include
C. fun
D. default
解析: