C ++中的继承与友谊
在C++中，友谊不是继承的。这意味着，如果一个父类具有某些友元函数，则子类将不会将它们作为朋友。
在此示例中，它将生成错误，因为display()函数是MyBaseClass的朋友，而不是MyDerivedClass的朋友。display()可以访问MyBaseClass的私有成员。
示例
#include <iostream>
using namespace std;
class MyBaseClass {
protected:
int x;
public:
MyBaseClass() {
x = 20;
}
friend void display();
};
class MyDerivedClass : public MyBaseClass {
private:
int y;
public:
MyDerivedClass() {
x = 40;
}
};
void display() {
MyDerivedClass derived;
cout << "The value of private member of Base class is: " << derived.x << endl;
cout << "The value of private member of Derived class is: " << derived.y << endl;
}
main() {
display();
}输出结果
[Error] 'int MyDerivedClass::y' is private [Error] within this context