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C++中类与类之间存在着两种名称遮盖关系，变量遮盖、函数遮盖。其本质都是名字的查找方式导致的，当编译器要找一个名字，它一旦找到一个相符的名字，就不会往下找了，因此遮掩本质上是优先查找那个名字的问题。
//：采用using声明，使查找范围扩大至父类指定的函数：class Base{public:void CommonFunction(){cout << "Base::CommonFunction()" << endl;}void virtual VirtualFunction(){cout << "Base::VirturalFunction()" << endl;}void virtual VirtualFunction(int x){cout << "Base::VirtualFunction() With Parms" << endl;}void virtual PureVirtualFunction() = 0;};class Derived: public Base{public:using Base::VirtualFunction; // 第一级查找也要包括Base::VirtualFunctionvoid CommonFunction(){cout << "Derived::CommonFunction()" << endl;}void virtual VirtualFunction(){cout << "Derived::VirturalFunction()" << endl;}void virtual PureVirtualFunction(){cout << "Derived::PureVirtualFunction()" << endl;}};int main(){Derived d;d.VirtualFunction(3); // 这样没问题了，编译器会把父类作用域里面的函数名VirtualFunciton也纳入第一批查找范围，这样就能发现其实是父类的函数与main中的调用匹配得更好（因为有一个形参），这样会输出Base::VirtualFunction() With Parmsreturn 0;}
//：使用转交函数强制指定父类的作用域class Base{public:void CommonFunction(){cout << "Base::CommonFunction()" << endl;}void virtual VirtualFunction(){cout << "Base::VirturalFunction()" << endl;}void virtual VirtualFunction(int x){cout << "Base::VirtualFunction() With Parms" << endl;}void virtual PureVirtualFunction() = 0;};class Derived: public Base{public:using Base::VirtualFunction;void CommonFunction(){cout << "Derived::CommonFunction()" << endl;}void virtual VirtualFunction(){cout << "Derived::VirturalFunction()" << endl;}void virtual PureVirtualFunction(int x){cout << "Derived::PureVirtualFunction()" << endl;}void virtual VirtualFunction(int x){Base::VirtualFunction(x)};};int main(){Derived d;d.VirtualFunction(3); // 输出Base::VirtualFunction() With Parmsreturn 0;}
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原文地址：http://www.cnblogs.com/chengkeke/p/5417380.html
