error LNK2019: 无法解析的外部符号 (新手求助)

[qq_28015407]

#include "stdafx.h"
#include "iostream"
#include "string"
#include "targetver.h"
 using namespace std;

 //////////////////////////////////////////////////////////////////////////基类
 class person
 {
 public:
	 string no;
	 string name;
	 person(string i,string j){ no=i;name=j;}
	 person();
	 ~person();
 };
 person::~person(){}
 /////////////////////////////////////////////////////////////////////////学生派生
 class student :private person
 {
private:
	 int Cno;
	 float score;
 public:
	 student (string n,string na,int cn,float s );
	 student();
	 void s_cin(student &s);
	 void display()
	 {
	  cout<<"编号："<< no<<endl;
	  cout<<"姓名："<< name<<endl;
	  cout<<"班号："<< Cno<<endl;
	  cout<<"成绩："<< score<<endl;
	 }
	 ~student();
 };
 /////////////////////////////////////////////////////////////////////////教师派生类
  class teacher :private person
 {
private:
	 string wname;
	 string wage;
 public:
	 teacher (string n,string na,string wn,string wa );
	 teacher();
	 void t_cin(teacher &t);
	 void display()
	 {
	  cout<<"编号："<< no<<endl;
	  cout<<"姓名："<< name<<endl;
	  cout<<"职称："<< wname<<endl;
	  cout<<"部门："<< wage<<endl;
	 }
	 ~teacher();
 };
  /////////////////////////////////////////////////////////////////////////
  student::student (string n,string na,int cn,float s ):person(n,na)
  {
	  Cno=cn;
	  score=s;
  }
  
  void student::s_cin(student &s)
  {
	cout<<"输入学生信息:"<<endl;
	cin>>s.no>>s.name>>s.Cno>>s.score;
  }
  student::~student(){}
  //////////////////////////////////////////////////////////////////////////
   teacher ::teacher(string n,string na,string wn,string wa ):person(n,na)
   {
	   wname=wn;
	   wage=wa;
   }

void teacher::t_cin(teacher &t)
  {
	cout<<"输入学生信息:"<<endl;
	cin>>t.no>>t.name>>t.wname>>t.wage;
  }
teacher::~teacher(){}
/////////////////////////////////////////////////////////////////
int _tmain(int argc, _TCHAR* argv[])
{
	teacher t;
	student s;
	s.s_cin(s);
	t.t_cin(t);
	s.display();
	t.display();
	return 0;
}

[ccrun.com]

三个类的默认构造函数没有实现，改成这样就行了：

//////////////////////////////////////////////////////////////////////////基类
class person
{
public:
	string no;
	string name;

	person(string i, string j)
	{
		no = i;
		name = j;
	}
	person() {}
	~person() {}
};

/////////////////////////////////////////////////////////////////////////学生派生
class student: private person
{
private:
	int Cno;
	float score;

public:
	student(string n, string na, int cn, float s);
	student() {}

	void s_cin(student &s);

	void display()
	{
		cout << "编号：" << no << endl;
		cout << "姓名：" << name << endl;
		cout << "班号：" << Cno << endl;
		cout << "成绩：" << score << endl;
	}
	~student();
};

/////////////////////////////////////////////////////////////////////////教师派生类
class teacher: private person
{
private:
	string wname;
	string wage;

public:
	teacher(string n, string na, string wn, string wa);
	teacher() {}

	void t_cin(teacher &t);

	void display()
	{
		cout << "编号：" << no << endl;
		cout << "姓名：" << name << endl;
		cout << "职称：" << wname << endl;
		cout << "部门：" << wage << endl;
	}
	~teacher();
};

/////////////////////////////////////////////////////////////////////////
student::student(string n, string na, int cn, float s): person(n, na)
{
	Cno = cn;
	score = s;
}

void student::s_cin(student &s)
{
	cout << "输入学生信息:" << endl;
	cin >> s.no >> s.name >> s.Cno >> s.score;
}

student::~student()
{
}

//////////////////////////////////////////////////////////////////////////
teacher::teacher(string n, string na, string wn, string wa): person(n, na)
{
	wname = wn;
	wage = wa;
}

void teacher::t_cin(teacher &t)
{
	cout << "输入学生信息:" << endl;
	cin >> t.no >> t.name >> t.wname >> t.wage;
}

teacher::~teacher()
{
}

/////////////////////////////////////////////////////////////////
int _tmain(int argc, _TCHAR *argv[])
{
	teacher t;
	student s;
	s.s_cin(s);
	t.t_cin(t);
	s.display();
	t.display();
	return 0;
}

[Eleven]

[oyljerry]

构造函数需要有实现，或者一个空函数

[孤客天涯]

楼上的都说得对，函数未实现

[qq_28015407]

谢谢大神们的指导