Need Help with Inheritence and containers

Hi everyone,
I need some help with homework please.

I have an Employee class and an Employees(container) class that sorted,added,deleted,and printed a simple payroll report.

My next assignment was to derive three classes  Hourly,Salaried,Piecework from class Employee. (done)

Now im trying to figure out how to incorperate the new derived types into the container.  as it stands now I cant becuase if I do this

Employee *pEmp = new Hourly(......);
Employees company;
company.add(pEmp) <--- this will not work it( plase see my container code)

Is there a way to incorperate my existing container with the derived classes? if not how would my data scheme be for a new one.?

Here is my code
===========================================
class Employee {
  private:
     char *lname;
     char *fname;
     float deffered;
     float gross;
     float net;
     float fedTax;
     float stateTax;
     float ssiTax;
     float calcFed(void) {return (gross-deffered)*FEDTAXRATE;}
     float calcState(void){return (fedTax * STATETAXRATE);}
     float calcSSI(void){return (gross-deffered)*SSITAXRATE;}

  public:
     Employee(const char*last="",const char* first="",float deff=0.0)
     :lname(NULL), fname(NULL),deffered(deff),gross(0), net(0), fedTax(0), stateTax(0), ssiTax(0)
     {
        int len = strlen(last);
        lname = new char[len+1];
        strcpy(lname, last);
        len = strlen(first);
        fname = new char[len+1];
        strcpy(fname, first);

      }
      ~Employee()//destruct
      {
          delete [] fname;
          delete [] lname;
      }
     Employee(const Employee& e) //copy
     :lname(NULL), fname(NULL),deffered(e.deffered),gross(e.gross), net(e.net), fedTax(e.fedTax),stateTax(e.stateTax), ssiTax(e.ssiTax)
     {  int len = strlen(e.lname);
        lname = new char[len+1];
        strcpy(lname, e.lname);
        len = strlen(e.fname);
        fname = new char[len+1];
        strcpy(fname, e.fname);
     }
     //Get services
     char* getLastName(void)const{return lname;}
     char* getFirstName(void)const{return fname;}
     const float getDeffered(void)const{return deffered;}
     const float getGross(void)const{return gross;}
     const float getNet(void)const{return net;}
     const float getFedTax(void)const{return fedTax;}
     const float getStateTax(void)const{return stateTax;}
     const float getSSITax(void)const{return ssiTax;}
     
     //change services
     void setLastName(const char * last){ int len =strlen(last);lname = new char[len+1];strcpy(lname, last);}
     void setFirstName(const char * first){int len =strlen(first);fname = new char[len+1];strcpy(fname, first);}
     void setDeffered(const float def){deffered=def;}
     void setGross(const float f){gross=f;}

     virtual void calcGross(void){}
   
     void calcNet(void);
     Employee operator = (const Employee &e); //overloaded = for swapping

};
void Employee::calcNet(void)
{
     this->fedTax = calcFed();
     this->stateTax = calcState();
     this->ssiTax = calcSSI();
     this->net = gross-(fedTax+stateTax+ssiTax+deffered);
  }
 

Employee Employee::operator =(const Employee &e)
{
  int len = strlen(e.fname);
  this->fname = new char[len+1];
  strcpy(fname, e.fname);
  len = strlen(e.lname);
  this->lname = new char[len+1];
  strcpy(lname, e.lname);
  this->deffered=e.deffered;
  this->gross=e.gross;
  this->fedTax=e.fedTax;
  this->ssiTax=e.ssiTax;
  this->stateTax=e.stateTax;
  this->net=e.net;
  return(e);
}
==================================================
class Hourly : public  Employee{

   private:
      float hours;
      float payrate;
   public:
      Hourly(char * last="",char *first="",float pr=0,float hr=0,float deff=0)
      {
         int len = strlen(last);
         this->setLastName(new char[len+1]);
         this->setLastName(strcpy(this->getLastName(), last));
         len = strlen(first);
         this->setFirstName(new char[len+1]);
         this->setFirstName(strcpy(this->getFirstName(), first));
         (deff<0)?this->setDeffered(0):this->setDeffered(deff);
         (hr<0)?hours=0:hours=hr;
         (pr<0)?payrate=0:payrate=pr;
      }
      void calcGross()
      {
         if(hours <= 40)
          this->setGross(hours * payrate);
         else
          this->setGross( 40 * payrate + (hours-40)* 1.5 * payrate);
      }
};
===========================================================
class PieceWork : public  Employee{
   private:
      float pieces;
      float payPerPiece;
   public:
      PieceWork(char * last="",char *first="",float NumPieces=0,float ppp=0,float deff=0)
      {
         int len = strlen(last);
         this->setLastName(new char[len+1]);
         this->setLastName(strcpy(this->getLastName(), last));
         len = strlen(first);
         this->setFirstName(new char[len+1]);
         this->setFirstName(strcpy(this->getFirstName(), first));
         (deff<0)?this->setDeffered(0):this->setDeffered(deff);
         (NumPieces<0)?pieces=0:pieces=NumPieces;
         (ppp<0)?payPerPiece=0:payPerPiece=ppp;
      }
      void calcGross(){this->setGross(pieces*payPerPiece);}
};
========================================================
class Salary : public  Employee{

   private:
      float salary;
   public:
      Salary(void){salary=0;}
      Salary(char * last="",char *first="",float f=0,float deff=0)
      {
         int len = strlen(last);
         this->setLastName(new char[len+1]);
         this->setLastName(strcpy(this->getLastName(), last));
         len = strlen(first);
         this->setFirstName(new char[len+1]);
         this->setFirstName(strcpy(this->getFirstName(), first));
         (deff<0)?this->setDeffered(0):this->setDeffered(deff);
         (f<0)?salary=0:salary=f;
      }
      void setSalary(const float f){(f<0)?salary=0:salary=f;}
      const float getSalary()const{return salary;}
      void calcGross(){this->setGross(salary);}
};
========================================================
/ Dynamic Container Class stores Employees,sorts,adds,deletes
class Employees{
  private:
     Employee* allEmployees;
     int EmployeeCount;
     int EmployeeSize;
     void qs_lname(int left, int right);
  public:
     Employees(void) : allEmployees(NULL), EmployeeCount(0), EmployeeSize(0)
     {allEmployees= new Employee[EmployeeSize];}
     Employees(Employees& e) : allEmployees(NULL), EmployeeCount(e.EmployeeCount), EmployeeSize(e.EmployeeSize)
     {
      allEmployees= new Employee[e.EmployeeSize];
      for(int i=0;i<EmployeeSize;i++)
         allEmployees[i]=e.allEmployees[i];
     }
     ~Employees(void){delete [] allEmployees;}
     //change state
     void add(const Employee& e);
     void remove(const Employee &e);
     float search(const char* last);
     void quicksort(){qs_lname(0,EmployeeCount-1);}
     void printPayrollReport(void);
     const int getEmployeeCount(void)const{return EmployeeCount;}
};
void Employees::add(const Employee &e)
{
  if(e.getNet()>0)
  {
  int found=search(e.getLastName());
  if (found >= 0)
     allEmployees[found] = e;   // update the entry found
  else
  {   if (EmployeeCount < EmployeeSize)
         allEmployees[EmployeeCount++] = e;
      else
      {
         EmployeeSize += 32;//set the array to 32
         Employee* all = new Employee[EmployeeSize];
         for (int i = 0; i <  EmployeeCount; ++i)
            all[i] = allEmployees[i];
         delete [] allEmployees;
         allEmployees = all;
         allEmployees[EmployeeCount++] = e;
   }
 }
}
else
{cout<< "Error: net is not calculated";
}
}
float Employees::search(const char* last)
{  for(int i=0;i<EmployeeSize;i++)
  {   if(strcmp(last, allEmployees[i].getLastName())==0)
         return i;
  }
  return-1;
}

void Employees::qs_lname(int left, int right)
{  int i, j;
  const char *x; // temp string
  i = left; j = right;
  x = allEmployees[(left+right)/2].getLastName(); // sorting by last name
  do
  {  while((strcmp(allEmployees[i].getLastName(),x) < 0) && (i < right))i++;
     while((strcmp(allEmployees[j].getLastName(),x) > 0) && (j > left)) j--;
     if(i <= j)
     { // swap
        Employee temp =allEmployees[i];
        allEmployees[i] = allEmployees[j];
        allEmployees[j] = temp;
        i++; j--;
     }
   } while(i <= j);
   if(left < j) qs_lname(left, j);
   if(i < right) qs_lname(i, right);
}
void Employees::remove(const Employee &e)
{
  int found=search(e.getLastName());
  if (found >= 0)
  {
     char erased[] = { char(255), '\0' };  
     Employee erase(erased);
     allEmployees[found] = erase;// set it to a new employee
     quicksort();
     Employee empty;
     allEmployees[--EmployeeCount] = empty;   // set it to a new employee
  }
}


Thanks so much for your help