一道题 C++ - 锐客网

定义基类Base，有两个共有成员函数fn1()、fn2()，私有派生出Derived类，如果想在Derived类的对象中使用基类函数fn1()，应怎么办？
我的代码:

#include using namespace std; class Base { public: Base(){} ~Base(){} void fn1(); void fn2(); }; void Base::fn1() { cout << "Base fn1 is used." << endl; }void Base::fn2() { cout << "Base fn2 is used." << endl; }class Derived :public Base { public: Derived(){} ~Derived(){} }; int main() { Derived n; n.fn1(); n.fn2(); return 0; }

教程的代码：

#include using namespace std; class Base { public: int fn1() const { cout << "Base fn1 is used." << endl; return 1; } int fn2() const { cout << "Base fn2 is used." << endl; return 2; } }; class Derived : private Base { public: int fn1() { cout << "Derived fn1 is used." << endl; return **Base::fn1(); ** }; int fn2() { cout << "Derived fn2 is used." << endl; return **Base::fn2(); ** }; }; int main() { Derived derive; derive.fn1(); derive.fn2(); return 0; }

【一道题】不是很明白加粗地方的想法。