7_67.cpp

几个C++程序设计实例

#include <iostream.h>
class cB
{
	public:
		cB(int v=7)
		{	B_value=v;
			cout<<"construct cB. B_value="<<B_value<<endl;
		}
		~cB()
		{	cout<<"destruct cB. B_value="<<B_value<<endl;
		}
	protected:
		int B_value;
};
class cA
{
	protected:
		int a;
		cB b;
	public:
		cA(int v1,int v2=3):b(v2)     //使用冒号语句调用类成员的"有参"构造函数
		{	a=v1;
			cout<<"construct cA. a="<<a<<endl;
		}
		~cA()
		{	cout<<"destruct cA."<<endl;
		}
};
void main()
{ 	cA a1(5,10);
	cA a2(5);
	cB b1(18);
}