45 C++ - 继承中同名成员的处理方法

原创

阿甘兄_ 2021-07-08 09:40:00 ©著作权

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1.当子类成员和父类成员同名时，子类依然从父类继承同名成员

2.如果子类有成员和父类同名，子类访问其成员默认访问子类的成员(本作用域，就近原则)

3.在子类通过作用域::进行同名成员区分(在派生类中使用基类的同名成员，显示使用类名限定符)

class Base{
public:
	Base():mParam(0){}
	void Print(){ cout << mParam << endl; }
public:
	int mParam;
};

class Derived : public Base{
public:
	Derived():mParam(10){}
	void Print(){
		//在派生类中使用和基类的同名成员,显示使用类名限定符
		cout << Base::mParam << endl;
		cout << mParam << endl;
	}
	//返回基类重名成员
	int& getBaseParam(){ return  Base::mParam; }
public:
	int mParam;
};

int main(){

	Derived derived;
	//派生类和基类成员属性重名，子类访问成员默认是子类成员
	cout << derived.mParam << endl; //10
	derived.Print();
	//类外如何获得基类重名成员属性
	derived.getBaseParam() = 100;
	cout << "Base:mParam:" << derived.getBaseParam() << endl;

	return EXIT_SUCCESS;
}

注意: 如果重新定义了基类中的重载函数，将会发生什么？

class Base{
public:
	void func1(){
		cout << "Base::void func1()" << endl;
	};
	void func1(int param){
		cout << "Base::void func1(int param)" << endl;
	}
	void myfunc(){
		cout << "Base::void myfunc()" << endl;
	}
};
class Derived1 : public Base{
public:
	void myfunc(){
		cout << "Derived1::void myfunc()" << endl;
	}
};
class Derived2 : public Base{
public:
	//改变成员函数的参数列表
	void func1(int param1, int param2){
		cout << "Derived2::void func1(int param1,int param2)" << endl;
	};
};
class Derived3 : public Base{
public:
	//改变成员函数的返回值
	int func1(int param){
		cout << "Derived3::int func1(int param)" << endl;
		return 0;
	}
};
int main(){

	Derived1 derived1;
	derived1.func1();
	derived1.func1(20);
	derived1.myfunc();
	cout << "-------------" << endl;
	Derived2 derived2;
	//derived2.func1();  //func1被隐藏
	//derived2.func1(20); //func2被隐藏
	derived2.func1(10,20); //重载func1之后，基类的函数被隐藏
	derived2.myfunc();
	cout << "-------------" << endl;
	Derived3 derived3;
	//derived3.func1();  没有重新定义的重载版本被隐藏
	derived3.func1(20);
	derived3.myfunc();

	return EXIT_SUCCESS;
}