Person.h

#ifndef?PEERSON_H
#define?PEERSON_H
#include?<string>
using?namespace?std;

class?Person{
public:
	Person(string?n);
	virtual?~Person(){}
	virtual?void?work()=0;
protected:
	string?Name;
};
#endif

Person.cpp

#include?"Person.h"

Person::Person(string?n){
????Name=n;
}

Worker.h

#ifndef?WORKER_H
#define?WORKER_H
#include?"Person.h"

class?Worker:public?Person{
public:
	Worker(string?n,int?a);
	virtual?void?work();
protected:
	int?Age;
};
#endif

Worker.cpp

#include?"Worker.h"
#include?<iostream>

Worker::Worker(string?n,int?a):Person(n){
????Age=a;
}
void?work(){
????//cout<<Name<<"?is?"<<Age<<endl;
????cout<<"work--worker"<<endl;
}

這個地方就不能用cout<<Name<<"?is?"<<Age<<endl，編譯說Name和Age未定義，之前的課程未涉及純虛函數時是正常的。

Dustman.h

#include?"Worker.h"

class?Dustman:public?Worker{
public:
	Dustman(string?n,int?a);
	virtual?~Dustman(){}
	void?work();
};

Dustman.cpp

#include?"Dustman.h"
#include?<iostream>

Dustman::Dustman(string?n,int?a):Worker(n,a){
}
void?Dustman::work(){
	cout<<Name<<"?is?"<<Age<<"?--Dustman"<<endl;
}

這里編譯又正常了，可以用Name和Age，求教上面為什么不能用

demo.cpp

#include?"Dustman.h"

int?main(){
	/*Dustman?dd("merry",18);
	dd.work();*/
	
	Person?*p?=?new?Dustman("merry",18);
	p->work();
	delete?p;
	p=NULL;
	return?0;
}

用2種實例化都不行，報錯一樣的

/tmp/cc8z9iC2.o: In function `Worker::~Worker()':

Dustman.cpp:(.text._ZN6WorkerD2Ev[_ZN6WorkerD5Ev]+0x7): undefined reference to `vtable for Worker'

/tmp/cc8z9iC2.o:(.rodata._ZTI7Dustman[_ZTI7Dustman]+0x8): undefined reference to `typeinfo for Worker'

/tmp/ccEPTJOC.o: In function `Worker::Worker(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, int)':

Worker.cpp:(.text+0x53): undefined reference to `vtable for Worker'

啥意思？我沒定義~Worker()這個函數啊

求糾錯

ps:編譯時就報錯了，還沒到運行的步驟