求纠错，实例化后无法编译，不晓得错在哪
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;
};
#endifPerson.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;
};
#endifWorker.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;
}这个地方就不能用cout<<Name<<" is "<<Age<<endl，编译说Name和Age未定义，之前的课程未涉及纯虚函数时是正常的。
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;
}这里编译又正常了，可以用Name和Age，求教上面为什么不能用
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种实例化都不行，报错一样的
/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？我没定义~Worker()这个函数啊
求纠错
ps:编译时就报错了，还没到运行的步骤
