摘要：
pass by value need to call constructor and desructor so not efficient.but exept for built-in type and stl :: iterator and 函数对象 阅读全文
摘要：
not really understand 阅读全文
摘要：
举一个容易犯错的例子class Date{private: int month; int day; int year;public:Date(int month,int day,int year){ this->month = month; ... }}//wrong exampleDa... 阅读全文