对象成员的有参构造的初始化列表

//对象成员的有参构造的初始化列表的使用:
#include<iostream>
using namespace std;
class A
{
private:
	int mA;
public:
	//A的初始化:
	void AInit(int a)
	{
		mA = a;
	}
	//A的无参构造:
	A()
	{
		mA = 0;
		cout << "A的无参构造" << endl;
	}
	//A的有参构造:
	A(int a)
	{
		mA = a;
		cout << "A的有参构造" << endl;
	}
	//A的析构函数:
	~A()
	{
		mA = 0;
		cout << "A的析构函数" << endl;
	}
};
class B
{
private:
	int mB;
	A aa;
public:
	//B的无参构造:
	B()
	{
		cout << "B的无参构造" << endl;
	}
	//B的有参构造:(A的无参构造)
	B(int b)
	{
		mB = b;
		cout << "B的有参构造,A的无参构造" << endl;
	}
	//B的有参构造:(A的有参构造)(初始化列表)
	B(int a,int b):aa(a)
	{
		mB = b;
		cout << "B的有参构造,A的有参构造" << endl;
	}
	//B的析构函数:
	~B()
	{
		cout << "B的析构函数" << endl;
	}
};
int main()
{
	B b1(10, 10);
	return 0;
}