is-a关系  类包含关系

构造 拷贝构造函数 重载福值运营商 析构函数

动态内存分配和释放 new delete操作

static 数据成员

好友功能 重载输入>>输出<<操作符

#include
     
      #include 
      
       using namespace std;class person {private:	char *name;	int age;public:	person()	{//class memeber has default value is necessary (or error may occur in person& operator=(const person &ps)  delete [] name )		cout << "call Person constructor() ..." << endl;		name = new char[20];		strcpy(name,"NULL");		age = 0;	}	person(char *n,int a)	{		cout << "call Person constructor(char *n,int a)..." << endl;		name = new char[strlen(n) + 1];		strcpy(name,n);		//name=n;//--error may ocurr when call ~person()  delete[] name		age=a;	}	//	person(person &ps)	{		cout << "call Person copy constructor..." << endl;		name = new char[strlen(ps.name) + 1];		strcpy(name,ps.name);		age = ps.age;	}	//	person& operator=(const person &ps)	{		cout << "call person operator=() ..." << endl;		if(this == &ps)			return *this;				delete []name;		name = new char[strlen(ps.name) + 1];				strcpy(name,ps.name);		age = ps.age;		return *this;//------return person &	}	friend istream & operator>>(istream &is, person &ps);//return value type :  ---istream &	friend ostream & operator<<(ostream &os,const person &ps);	void show()	{		cout<<"name:" << name<<" age:"<
       
        << endl;	}	 ~person()	{		cout << "call person destructor..." << endl;		delete [] name;	}};istream & operator>>(istream &is, person &ps){		cout << "input name :" << endl;		is >> ps.name;		cout << "input age:" << endl;		is >> ps.age;		return is;}ostream & operator<<(ostream &os,const person &ps){	os <<"name:" << ps.name<<" age:"<
        
         << endl;	return os;}class student{private:	person s;//include person class	static int sno;	char *grade;	int score;public:	student()	{		cout << "Call student constructor()..." << endl;		grade = new char[20];		strcpy(grade,"no");		sno++;		score=0;	}	student(char *n,int a,char *g,int sc):s(n,a)/*,grade(g)*/,score(sc)	{		cout << "call Student constructor(char *n,int a...)..." << endl;		sno++;		grade = new char[strlen(g) + 1];		strcpy(grade,g);		cout<<"sno:" << sno << " score:" << score<< " grade: "<
         
          <
          
           >(istream &is,/*const */student &st) { operator>>(is,st.s);//输入内部对象成员的值 (调用内部类的友元函数--istream & operator>>(istream &,person &ps)) cout << "input sno: " << endl; is >> st.sno; cout << "input score:" << endl; is >> st.score; cout << "input grade:" << endl; is >> st.grade; return is; } friend ostream &operator<<(ostream &os,const student &st) { operator<<(os,st.s);//输出内部对象成员的值 (调用内部类的友元函数 --ostream & operator<<(ostream &,const student &st)) os<<"sno: " << st.sno<<" grade:"<
           
            <<" score:"<
            
             <
             
              >() 。ostream & operator<<()... " << endl; person p; cin >> p; cout << p;// p.show(); cout << "-----------------" << endl; student s; cin >> s; cout << s; //s.display();// system("pause"); student A("Tom",21,"Freshman",99); A.display(); cout << "*************************" << endl; student B(A); B.display(); cout << "*************************" << endl; person p1("li",25); person p2;// p2 = p1; p2.show(); cout << "*************************" << endl; student C = A; C.display(); cout << "************************" << endl; student D; D = B; D.display();}
             
            
           
          
         
        
       
      
     

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