3 unresolved externals

#include <iostream>
#include <string>
#include "conio.h"
#include <vector>
#include <set>
#include <numeric>
using namespace std;
 
void getaLine(string&  inStr) 
{
    char temp[21];
    cin.get(temp, 20, '\n');
    cin.ignore(20, '\n');
    inStr = temp;
}
char getaChar()
{
    char ch = cin.get();
    cin.ignore(80,'\n');
    return ch;
}
 
class Person
{
protected:
    string Name;
public:
 
    Person (string nName): Name(nName)
    {}
    virtual ~Person();
 
    virtual void getData() = 0;
    
    friend ostream& operator << (ostream&, Person&);
    friend istream& operator >> (istream&, Person&);
    friend bool operator < (const Person&, const Person&);
    friend bool operator == (const Person&, const Person&);
};
 
class compareMan
{
public:
    bool operator ()(Person*, Person*) const;
};
 
class Man : public Person
{
private:
    
public:
    Man (string nName): Person(nName)
    {}
 
    ~Man()
    {}
 
    void getData()
    {
    cout << "\n" << endl;
    }
};
 
 
 
 
class ListPerson
{
private:
    set<Man* , compareMan > setMan;
    set<Man* , compareMan> :: iterator iter;
 
public:
 
    ~ListPerson()
        {
    while(!setMan.empty())
    {
    iter = setMan.begin();
    delete *iter;
    setMan.erase(iter);
    }
    }
 
    void insertMan(Man* ptrMan)
    {
    setMan.insert(ptrMan);
    }
 
    void display()
    {
 
    cout << "Name Person" << endl;
    if (setMan.empty())
        cout << "Not Persons" << endl;
    else 
    {
 
    iter = setMan.begin();
    while(iter != setMan.end())
        cout << **iter++;
    
    }
    }
 
};
 
class ScreenPerson
{
private:
 
    ListPerson* ptrListPerson;
    string pName;
 
public:
    ScreenPerson(ListPerson* ptrLP) : ptrListPerson(ptrLP)
    {}
 
    void getPerson()
    {
        cout << "Vvedite Name:" << endl;
        getaLine(pName);
        Man* ptrMan = new Man (pName);
        ptrListPerson -> insertMan(ptrMan);
    }
};
 
class Weight
{
private:
    float Paper[5];
public:
 
    Weight(int  pPaper)
 
    {fill (&Paper[0], &Paper[5], 0);}
 
    void setWeight(int d, float am)
    {
    Paper[d] = am;
    }
 
 
 
    float getSumWeight()
    {
    return accumulate(&Paper[0], &Paper[5], 0);
    }
 
 
 
    friend ostream& operator << (ostream& s, const Weight& an)
    {
    for (int j = 0; j < 5; j++)
    {
    if(an.Paper[j] == 0)
        s << " 0 ";
    else 
        s << an.Paper[j] << " " ;
    }
    s << endl;
 
    return s;
    
    }
 
};
 
class compareWeight
{
public:
    bool operator ()(Weight*, Weight*) const;
        
};
 
class WeightRecord
{
private:
    set < Weight* , compareWeight > setWeight;
    set < Weight* , compareWeight > :: iterator iter;
public:
    ~WeightRecord()
    {
    
    while( !setWeight.empty())
    {
    iter = setWeight.begin();
    delete *iter;
    setWeight.erase(iter);
    
    }
    
    }
 
 
    void display()
    {
    cout << "\n\t 1 day 2 day 3 day 4 day 5 day\n"
         << "------------------------------------"
         << "------------------------------------\n";
    if (setWeight.empty())
        cout << "Non" << endl;
    else
    {
    iter = setWeight.begin();
    while(iter != setWeight.end())
        cout << **iter++;
    
    }
    }
 
    float getSumOfWeight()   //сумма всей сданной макулатуры
    {
        float sumKg = 0.0;
        iter = setWeight.begin();
        while(iter != setWeight.end())
        {
        sumKg += (*iter) -> getSumWeight();
        iter++;
        }
        return sumKg;
    }
};
class InputWeightScreen
{
private:
    ListPerson* ptrListPerson;
    WeightRecord* ptrWeightRecord;
 
    string WeightName;
    float kg;
    int day;
    
public:
    InputWeightScreen(ListPerson* ptrLP, WeightRecord* ptrWR) :
      ptrListPerson(ptrLP), ptrWeightRecord(ptrWR)
      {}
 
    void getWeight()// сдано за день кг
    {
    cout << "Name";
    getaLine(WeightName);
 
 
    cout << "Kg";
    cin >> kg;
    cin.ignore(80, '\n');
 
    cout << "day";
    cin >> day;
    cin.ignore(80, '\n');
    day--;
    
    
    
    }
 
    
};
 
 
class Input
{
private:
 
    ListPerson* ptrListPerson;
    WeightRecord* ptrWeightRecord;
    ScreenPerson* ptrScreenPerson;
    InputWeightScreen* ptrInputWeightScreen;
    char ch;
 
public:
 
    Input()
    {
    ptrListPerson = new ListPerson;
    ptrWeightRecord = new WeightRecord;
    }
 
    ~Input()
 
    {
    delete ptrListPerson;
    delete ptrWeightRecord;
    }
 
 
 
 
    void Interact()
 
    {
 
    while(true)
 
    {
    cout << "wwod dannych  'i' , \n"
         << "        'd' otczet,\n"
         << "       'q' wychod:" << endl;
 
    ch = getaChar();
 
    if(ch == 'i')
 
    {
        cout << " 't' dobawic person,\n"
             << " 'r' zapis  kg,\n";
 
        ch = getaChar();
 
        switch(ch)
 
        {
 
        case 't' :ptrScreenPerson = new ScreenPerson(ptrListPerson);
            ptrScreenPerson -> getPerson();
            delete ptrScreenPerson;
            break;
 
        case 'r' : ptrInputWeightScreen = new InputWeightScreen(ptrListPerson, ptrWeightRecord);
            ptrInputWeightScreen -> getWeight();
            delete ptrInputWeightScreen; 
            break;
 
        default : cout << "neizwestnaja funkcija\n";
            break;
            
        }
    }
    else if(ch == 'd')
 
    {
    cout << " 't' dlia wiwoda person \n"
         << "'r' dlia wywoda raschodow \n";
    
    ch == getaChar();
 
    switch(ch)
 
    {
    case 't' : ptrListPerson -> display();
        break;
 
    case 'r' : ptrWeightRecord -> display();
        break;
 
    default: cout << "neizwestnaja funkcija\n"; 
        break;
 
    
    }
    }
 
    else if( ch == 'q')
 
    return;
 
    else 
        cout << "Neizwestnaja funkcija , tolko 'i' , 'd' , 'q' \n";
    
    }
    
    }
};
 
 
 
int main()
{
    Input person;
 
    person.Interact();
        
 
return 0;
}

case 't' :
           {
                ptrScreenPerson = new ScreenPerson(ptrListPerson);
                ptrScreenPerson -> getPerson();
                delete ptrScreenPerson;
                break;
            }