由于这里探讨的是 C++ 的 copy constructor, 因此简单地说, 如果一个类拥有资源,当这个类的对象发生复制过程的时候,资源重新分配,这个过程就是深拷贝,反之,没有重新分配资源,就是浅拷贝, 书里的 bitwise copy semantics 就是所谓的"浅拷贝", 而 memberwise 则是所谓的 "深拷贝". 这即是说, 只有对于 class ...
(1)class内含一个或多个成员对象,且这些member object中至少一个存在copy constructor(无论是显式的copy constructor还是隐式的no bitwise copy constructor) (2)class派生自一个继承串链,其中至少有一个base class存在copy constructor(再次强调,无论是显式的copy constructor还是隐式的no bitwise copy constructor) ...
那么当编译器隐式定义的默认构造函数是一个 non-trivial default constructor 时,该 non-trivial default constructor 调用这个类的各基类和各非静态成员的默认构造函数 通过以上,我们已经知道了编译器在特定情况下,真的会隐式定义一个 default constructor,也知道了在哪些情况下产生的 default constructor 是 trivial 的...
Why is it recommended to provide implementation of copy constructor instead of using compiler provided" default copy constructor"? This is in reference to create new instance of Class from existing one. Foo object2 = object1 ; Jan 4, 2009 at 10:39am ...
对于一个copy-constructor and copy-assignment operator,拷贝就相当于直接memcpy()直接复制内存过去;总之两...
The default constructor (12.1), copy constructor and copy assignment operator (12.8), and destructor (12.4) arespecial member functions.The implementation will implicitly declare these member functions for a class type when the program does not explicitly declare them, except as noted in12....
In this case the copy constructor of vector<T> is a bit of a mix. It will deeply copy the underlying storage such that each vector<T> has it's own independent array. However it will copy the elements using the copy constructor. In this case it's a pointer type hence they are ...
You could delete the default copy constructor or default copy assignment operator for each base class, but that would be onerous and result in lots of duplicated code. Also, the deletion would get hidden among the base class methods.
// constructor X(int, int , int = 0); // copy constructor X(const X&); // error, incorrect argument type X(X); }; class Y { public: // default constructor with one // default argument Y( int = 0); // default argument ...
() got called. So I knew that the copy constructor for Person got called, but I couldn't know if the copy constructor for Woman got called, but that wouldn't really matter, since p is a Person, and through it I'd never have access to Woman::Hotness, not even if I tried a cast...