Status matching(SqStack &S,string &exp){int state=1;int i=0;SElemType e;while(i<strlen(exp)&&state)//這里出錯。//cannot convert parameter 1 from 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >' to 'const char *'No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called