5，

//几个类（Vehicle类 Car类 Streetwheel类 Brake类）有着必然的联系，设计类与实现
#include<iostream>
using namespace std;
class Vechile{
	public:
		virtual void function() = 0;
};
class Streetwheel{
	public:
		Streetwheel(int x):diameter(x){}
		void getdiameter(){
			cout<<"轮子直径为："<<diameter<<endl; 
		}
	private:
		int diameter;
		
};

class Brake{
	public:
		void stop(){
			cout<<"stop-----"<<endl;
		}
		
};
class Car:public Vechile{
	public:
		Car():w(4){
		}
		virtual void function(){
			cout<<"我是小汽车"<<endl;
			w.getdiameter();
			b.stop();	 
		}
		
	private:
		Streetwheel w;
		Brake b;
};

	
int main(){
	Car c ;
	c.function();
	return 0;
}

6，

//一个基类 Shape，在基类的基础上继承写一个二维图形类，再继承写一个三维图形类，设计与实现
#include<iostream>
using namespace std;
class Shape{
	public:
		virtual void area()=0; 
};
class towShape:public Shape{
	public:
		towShape(int l=0,int w=0):length(l),weight(w){}
		virtual void area()
		{
		int s;
		s = length*weight;
		cout<<"s="<<s<<endl;
		}
	protected://把他设置为protected了，下面的继承triShape才能直接用，若设置为private,要在该类中声明一个public 函数getheight,getweight来获取到 
		int length;
		int weight; 
};
class triShape:public towShape{
	public:
		triShape(int l=0,int w=0,int h=0):height(h),towShape(l,w){//构造函数初始化的形式 
		}
		virtual void area()
		{	int v;
			v = length*weight*height;
			cout<<"v="<<v<<endl; 
		};
	private:
		int height;		
};
	
int main(){
	triShape t(1,2,3);
	t.area();
	
	return 0;
}