1 编译器会为这个类的虚函数添加一个虚表,类似下面的: // Pseudo-code (not C++, not C) for a static table defined within file Base.cpp // Pretend FunctionPtr is a generic pointer to a generic member function // (Remember: this is pseudo-code, not C++ code) FunctionPtr Base::__vtable[...
c++virtual-functionsundefined-reference nit*_*ian 2017 07-21 7 推荐指数 2 解决办法 4566 查看次数 C++虚方法覆盖 可能重复: 在构造函数内调用虚函数 main.cpp中 #include<iostream>classBaseClass{public: BaseClass() { init(); }virtual~BaseClass() { deinit(); }virtualvoidinit(){std::cout<<"Bas...
// CPP program to illustrate// working ofVirtualFunctions#include<iostream>usingnamespacestd;classbase{public:voidfun_1(){cout<<"base-1\n"; }virtualvoidfun_2(){cout<<"base-2\n"; }virtualvoidfun_3(){cout<<"base-3\n"; }virtualvoidfun_4(){cout<<"base-4\n"; } };classderived:pu...
Functions with different return types: If the virtual function is, say, of void type but the function in the derived class is of int type. Functions with different parameters: If the parameters of the virtual function and the functions in the derived classes don't match. No virtual function...
Runtime polymorphism is achieved using these functions. So whenever a function in C++ is made virtual, the compiler at runtime decides which function it has to call based on the object pointed by the base class pointer. Example code:
Virtual Member Functions and Dynamic Binding Let's look at our simple examples. Virtual Method Example 1 #include <iostream> class A { public: void f() { std::cout << "A::f()" << std::endl; } }; class B: public A {
1、在继承中使用多态能力的时候，需要使用virtual functions机制；2、基类指针指向子类实例的时候，需要使用virtual析构函数；任何其他时候，virtual并没有其他你想要的任何魔力且会有反噬作用。其实还有一种情况需要virtual，就是virtual base class，由于这种情况太过于复杂，建议任何时候都不要去尝试它（可能需要另外一篇...
// deriv_VirtualFunctions2.cpp // compile with: /EHsc #include <iostream> using namespace std; class Base { public: virtual void NameOf(); // Virtual function. void InvokingClass(); // Nonvirtual function. }; // Implement the two functions. void Base::NameOf() { cout << "Base::Nam...
隐藏的指针放入对象,该指针称为“virtual-pointor”或“v-pointer”。这个v-pointer指向一个全局表,该表称为“虚函数表(virtural-table)”或“v-table”。 编译器为每个含有至少一个虚函数的类创建一个v-table。例如,如果Cirle类有虚函数ddraw()、move()和resize(),那么将有且只有一个和Cricle类相关的v-table...
提示使用virtual,override,final三个关键词的两个或三个的函数声明。 原文链接: https:///isocpp/CppCoreGuidelines/blob/master/#c128-virtual-functions-should-specify-exactly-one-of-virtual-override-or-final 觉得本文有帮助?欢迎点赞并分享给更多人。