求救！请问这是什么原因？

[herman~~]

// test619.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>
#include <string>
#include <list>
using namespace std;


class Employee{
string first_name;
string family_name;
short department;

public :
Employee(const string name,int dept);
virtual void print() const;
};
void Employee::print() const
{
cout<<family_name <<'\t'<<department<<'\n';
}

class Manager : public Employee{
list<Employee * >group ;
short level;

public:
Manager(const string& name, int dept,int lvl);
void print() const;
};

void Manager::print() const
{
Employee ::print();
cout<<"\tlevel"<<level <<'\n';
}

void print_list(const list<Employee *>& s)
{
for (list<Employee *> ::const_iterator p = s.begin();p!=s.end();++p)
(*p)->print();
}
int main(int argc, char* argv[])
{
Employee e("Brownn",1234);
Manager m("Smith",1234,2);
list<Employee*> empl;
empl.push_front(&e);
empl.push_front(&m);
print_list(empl);

return 0;
}
==================================



--------------------Configuration: test619 - Win32 Debug--------------------
Compiling...
test619.cpp
Linking...
test619.obj : error LNK2001: unresolved external symbol "public: __thiscall Manager::Manager(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &,int,int)" (??0Manager@@QAE@ABV?$basic_string@DU?$char_traits
@D@std@@V?$allocator@D@2@@std@@HH@Z)
test619.obj : error LNK2001: unresolved external symbol "public: __thiscall Employee::Employee(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,int)" (??0Employee@@QAE@V?$basic_string@DU?$char_traits@D@std@@V?$
allocator@D@2@@std@@H@Z)
Debug/test619.exe : fatal error LNK1120: 2 unresolved externals
Error executing link.exe.

test619.exe - 3 error(s), 0 warning(s)

[suxk]

class Employee{
public:
string first_name;
string family_name;
short department;

public :
Employee(const string name,int dept);
virtual void print() const;
};
构造函数没有实现函数体

[柯本]

class Employee 及class Manager的构造都没有实现

[herman~~]

问题解决了！
感谢楼上几位，揭贴，给分了

[不可触碰]

可能是你实现文件没有，要不就是lib文件没调入

[herman~~]

我没有调用什么lib文件呀？