C ++继承从基类指针访问派生类中的非虚函数

Question

Consider the following code for

class BankAccount
{
protected:
    int accNo;
    int balance;
    std::string custName;
    std::string custAddress;

public:
    BankAccount(int aNo, int bal,  std::string name, std::string address);//:accNo(aNo), balance(bal), custName(name), custAddress(address);
    BankAccount(const BankAccount&);
    BankAccount();
    ~BankAccount();
    BankAccount& operator=(const BankAccount&);

    int getAccNumber() const {return accNo;};
    virtual int getBalance() const {return balance;};
    std::string getAccountHolderName()const {return custName;};
    std::string getAccountHolderAddress()const {return custAddress;};
    virtual std::string getAccountType()const{return "UNKNOWN";};
};


class CurrentAccount:public BankAccount
{
private:
    int dailyTrancLimit;
public:
    CurrentAccount(int aNo, int bal,  std::string name, std::string address);
    int getTransactionLimit()const {return dailyTrancLimit;};
    void setTranscationLimit(int transLimit){dailyTrancLimit = transLimit;};
    std::string getAccountType()const{return "CURRENT";};

};

class SavingAccount:public BankAccount
{
private:
    int intrestRate;
    int accumuatedIntrest;
public:
    SavingAccount(int aNo, int bal,  std::string name, std::string address);
    int getBalance()const {return balance+accumuatedIntrest;};
    void setIntrestEarned(int intrest){accumuatedIntrest=intrest;};
    std::string getAccountType()const{return "SAVINGS";};

};

I want to call setIntrestEarned() in SavingAccount class with base class pointer. I don't want to add setIntrestEarned() as virtual in base class BankAccount because it has no meaning in the other type of accounts like derived one CurrentAccount .

And if we keep adding various function in different derived class as virtual in base class then it will end up like a superset of functions of derived class.

What would be the best way to design these type of class hierarchy?

Answer 1

If it has no meaning in your base class, then you do not need to inherit from it.

Inheritance is only useful in the form where: B is a subset of A. B can have exclusive functions that A does not have.

Hence, if your savingsacc class requires certain information that A contains, then inherit it, and create exclusive functions for B that A does not need as C may also be a subset of A.