在C++11新标准中，派生类能够重用其直接基类的构造函数
#include <iostream>
using namespace std;
struct Base
{
Base() { cout << "construct" << endl; }
};
struct Derived : public Base
{
using Base::Base; //继承Base的构造函数
};
int main()
{
Derived d;
return 0;
}
一个构造函数的声明不会改变该函数的访问级别
#include <iostream>
using namespace std;
struct Base
{
Base() { cout << "construct" << endl; }
};
struct Derived : public Base
{
private://不会改变继承的构造函数的访问级别，仍然是publiic
using Base::Base;
};
int main()
{
Derived d;
return 0;
}
当一个基类的构造函数含有默认实参，这些实参并不会被继承。相反，派生类将获得多个继承的构造函数
#include <iostream>
using namespace std;
struct Base
{
Base(int x=1) { cout << "construct" <<x<< endl; }
};
struct Derived : public Base
{
//实际上继承了2个构造函数
using Base::Base;
};
int main()
{
Derived d;
Derived d1(2);
return 0;
}
如果派生类定义的构造函数与基类的构造函数有相同的参数列表，该构造函数不会被继承
#include <iostream>
using namespace std;
struct Base
{
Base() { cout << "construct" << endl; }
Base(int) { cout << "construct int" << endl; }
};
struct Derived : public Base
{
using Base::Base;
//不会继承Base的默认构造函数
Derived() { cout << "Derived class construct" << endl; };
};
int main()
{
Derived d;
Derived d(1);
return 0;
}
