How to access derived class functions?

[jewel87]

Hi everyone,

i have problems with inheritance implementation. I have a base class Account and 3 derived classes from it: CurrentAccount, SavingAccount and ISAAccount.
The Account class is connected with the Employee class and i'm trying to use the derived class functions in the Employee class.
In the Employee i have declared a pointer

Account **theAccounts;

And here is the rest code.

Employee.cpp

//---------------------------------------------------------------------------
 
#include <vcl.h>
#pragma hdrstop
 
#include "Employee.h"
 
#include "CurrentAccount.h"
#include "SavingAccount.h"
#include "ISAAccount.h"
 
//---------------------------------------------------------------------------
 
void Employee :: create(TEdit *EnterEmployeeName,
                        TEdit *EnterEmployeeSurname,
                        TEdit *EnterEmployeeSocialNumber,
                        TEdit *EnterEmployeeSalary,
                        TEdit *EnterEmployeeHouseName,
                        TEdit *EnterEmployeeHouseNo,
                        TEdit *EnterEmployeeStreet,
                        TEdit *EnterEmployeeTown,
                        TEdit *EnterEmployeePostCode,
                        TEdit *EnterEmployeeCountry,
                        TEdit *EnterDOBdate,
                        TEdit *EnterDOBmonth,
                        TEdit *EnterDOByear,
                        TEdit *EnterEmploymentStartDate,
                        TEdit *EnterEmploymentStartMonth,
                        TEdit *EnterEmploymentStartYear,
                         TEdit *EnterBankCode,
                         TEdit *EnterAccountNo,
                         TEdit *EnterBalance,
                         TEdit *EnterBankName,
                         TEdit *EnterRate,
                         TEdit *EnterOverdraftLimit,
                         TEdit *EnterConditions)
{
       /////// some other stuff ...
 
        theAccounts[0]->create(EnterBankCode->Text,
                                StrToInt(EnterAccountNo->Text),
                                StrToFloat(EnterBalance->Text),
                                EnterBankName->Text,
                                StrToFloat(EnterRate->Text),
                                StrToFloat(EnterOverdraftLimit->Text),
                                EnterConditions->Text);      //////////////problem
 
}
 
void Employee :: display (TLabel *NameField,
                         TLabel *SurnameField,
                         TLabel *SocialNumberField,
                         TLabel *SalaryField,
                         TMemo *AddressMemo,
                         TLabel *DOBLabel,
                         TLabel *EmploymentStartDateLabel,
                         TLabel *BankCodeLabel,
                         TLabel *AccountNoLabel,
                         TLabel *BalanceLabel,
                         TLabel *BankNameLabel,
                         TLabel *RateLabel,
                         TLabel *OverdraftLimitLabel,
                         TLabel *ConditionsLabel)
 
{
 
             theAccounts[0]->display(BankCodeLabel,
                                   AccountNoLabel,
                                   BalanceLabel,
                                   BankNameLabel,
                                   RateLabel,
                                   OverdraftLimitLabel,
                                   ConditionsLabel);    /////// problem
 
       int flag = theAccounts[0]->CheckBalance();    //////derived class function-can't see
 
        if (flag == 1) ShowMessage("Your balance exceeds overdraft limit!");
 
}
 
 
Employee :: Employee()
{
        FirstName = "";
        Surname = "";
        SocialNumber = -1;
        Salary = -1;
        DOB = new clsDate();
        EmploymentStartDate = new clsDate();
        HomeAddress = new Address();
 
        theAccounts = new Account*[3];
         theAccounts[0] = new CurrentAccount();
        theAccounts[1] = new ISAAccount();
        theAccounts[2] = new SavingAccount();
 
}
 
Employee :: Employee(String aFirstName, String aSurname, double aSalary,
                        int aSocialNumber)
{
        FirstName = aFirstName;
        Surname = aSurname;
        Salary = aSalary;
        SocialNumber = aSocialNumber;
 
        HomeAddress = new Address();
        DOB = new clsDate();
        EmploymentStartDate = new clsDate();
 
        theAccounts = new Account*[3];
        theAccounts[0] = new CurrentAccount;
        theAccounts[1] = new ISAAccount;
        theAccounts[2] = new SavingAccount;
 
}
 
Employee :: ~Employee()
{
 
        //      delete HomeAddress;
          //   HomeAddress = NULL;
 
 
        delete DOB;
        delete EmploymentStartDate;
 
        delete theAccounts[0];
        delete theAccounts[1];
        delete theAccounts[2];
        delete theAccounts;
}
 
//---------------------------------------------------------------------------
 
#pragma package(smart_init)
 
 
 
 

Here is Account.h

//---------------------------------------------------------------------------
 
#ifndef AccountH
#define AccountH
 
#include<vcl.h>
 
//---------------------------------------------------------------------------
 
class Account{
        protected:
                  String BankCode;
                  int AccountNo;
                  double Balance;
                  String BankName;
                  double Rate;
 
        public:
                void create(String aBankCode,
                                int aAccountNo,
                                double aBalance,
                                String aBankName,
                                double aRate);
 
                void display(TLabel *BankCodeLabel,
                               TLabel *AccountNoLabel,
                               TLabel *BalanceLabel,
                               TLabel *BankNameLabel,
                               TLabel *RateLabel);
 
                void deposit(double Amount);
                void withdraw(double Amount);
 
                Account();
                ~Account();
 
 
};
 
 
//---------------------------------------------------------------------------
#endif
 
 

I won't include Account.cpp with function implementation, but then there is derived class CurrentAccount.

CurrentAccount.h

 
#ifndef CurrentAccountH
#define CurrentAccountH
 
#include "Account.h"
 
 
class CurrentAccount: public Account{
 
        private:
                double OverdraftLimit;
                String Conditions;
 
        public:
                void create(String aBankCode,
                            int aAccountNo,
                            double aBalance,
                            String aBankName,
                            double aRate,
                            double anOverdraftLimit,
                            String Conditions);
 
                void display(TLabel *BankCodeLabel,
                             TLabel *AccountNoLabel,
                             TLabel *BalanceLabel,
                             TLabel *BankNameLabel,
                             TLabel *RateLabel,
                             TLabel *OverdraftLimitLabel,
                             TLabel *ConditionsLabel);
 
                double CheckInterest(double EnteredBalance, double theRate);
                int CheckBalance();
 
                CurrentAccount(String aBankCode,
                                int aAccountNo,
                                double aBalance,
                                double aRate,
                                double anOverdraftLimit);
                CurrentAccount();
                ~CurrentAccount();
 
};
 
 

i am getting errors:
E2227 Extra parameter in call to Account::create(AnsiString,int,double,AnsiString,d ouble) ,
which means it expects the function parameters to be as in class Account function, although i expected the CurrentAccount to override the function, as the parameters are passed as declared in CurrentAccount functions.
And also,
F1004 Internal compiler error at 0xc4c4e7 with base 0xc10000

Both errors are in the line marked with ///////////problem, in the Employee.cpp
Before there was also an error that int CheckBalance(); is not a member of Account class, but i don't see it now.

What is wrong?? Any help will be appreciated!

[Ganon11]

Have a look at what the virtual keyword does. You need it in C++ to properly implement polymorphism and inheritance.

[jewel87]

Have a look at what the virtual keyword does. You need it in C++ to properly implement polymorphism and inheritance.

Thanks, i've declared Account functions as virtual, but i'm still having problems:

Employee.cpp(64): E2227 Extra parameter in call to Account::create(AnsiString,int,double,AnsiString,d ouble)

Employee.cpp(64): F1004 Internal compiler error at 0xc4c4e7 with base 0xc10000

And it doesn't see the CheckBalance() function, that is it is searching for it in the Account class, which doesn't have it.
I've read these topics in many books and on the net, but can't resolve this.;(((
Please help me, people!

[weaknessforcats]

Employee.cpp(64): E2227 Extra parameter in call to Account::create(AnsiString,int,double,AnsiString,d ouble)

The compiler thinks Account::create has 5 arguments. Your code has many more. That is, your call does not jibe with the class definition (which you didn't post).