深入理解C++11 C3

class A
{
public:
	A(int i):m_i(i) {}
	A(double d, int i):m_d(d),m_i(i){}
private:
	int m_i{0};
	double m_d{0};
};

class B : public A
{
	using A::A;    // C++11 继承结构函数
	int m_j{ 0 };  // C++11 成员变量初始化
};

int main()
{
	B b1(356);
	B b2(2.0, 5);
	std::cout << "Hello World!\n"; 
}
class A
{
public:
	A(int i):m_i(i) {}
	A(d