普通类继承

#ifndef _BRASS_H_
#define _BRASS_H_

#include <string>

//Brass Account Class
class Brass
{
private:
    std::string fullName;
    long acctNum;
    double balance;

public:
    Brass(const std::string & s = "Nullbody", long an = -1, double bal = 0.0);
    void Deposit(double amt);
    virtual void Withdraw(double amt);
    double Balance(void) const;
    virtual void ViewAcct(void) const;
    virtual ~Brass() {}
};

//Brass Plus Account Class
class BrassPlus : public Brass
{
private:
    double maxLoan;
    double rate;
    double owesBank;

public:
    BrassPlus(const std::string & s = "Nullbody", long an = -1, double bal = 0.0, double ml = 500, double r = 0.11125);
    BrassPlus(const Brass & ba, double ml = 500, double r = 0.11125);
    virtual void ViewAcct(void) const;
    virtual void Withdraw(double amt);
    void ResetMax(double m)
    {
        maxLoan = m;
    }
    void ResetRate(double r)
    {
        rate = r;
    }
    void ResetOwes(void)
    {
        owesBank = 0;
    }
};

#endif

#include <iostream>
#include "brass.h"
using std::cout;
using std::endl;
using std::string;

//formatting stuff
typedef std::ios_base::fmtflags format;
typedef std::streamsize precis;
format setFormat(void);
void restore(format f, precis p);

//Brass methods
Brass::Brass(const string & s, long an, double bal)
{
    fullName = s;
    acctNum = an;
    balance = bal;
}

void Brass::Deposit(double amt)
{
    if(amt < 0)
    {
        cout << "Negative deposit not allowed; " << "deposit is cancelled." << endl;
    }
    else
    {
        balance += amt;
    }
}

void Brass::Withdraw(double amt)
{
    //set up ###.## format
    format initialState = setFormat();
    precis prec = cout.precision(2);

    if(amt < 0)
    {
        cout << "Withdrawal amount must be positive; " << "withdrawal canceled." << endl;
    }
    else if(amt <= balance)
    {
        balance -= amt;
    }
    else
    {
        cout << "Withdrawal amount of $" << amt << " exceeds your balance." << endl << "Withdrawal canceled." << endl;
    }

    restore(initialState, prec);
}

double Brass::Balance(void) const
{
    return balance;
}

void Brass::ViewAcct(void) const
{
    //set up ###.## format
    format initialState = setFormat();
    precis prec = cout.precision(2);

    cout << "Client: " << fullName << endl;
    cout << "Account Number: " << acctNum << endl;
    cout << "Balance: $" << balance << endl;

    restore(initialState, prec);
}

//BrassPlus methods
BrassPlus::BrassPlus(const string & s, long an, double bal, double ml, double r) : Brass(s, an, bal)
{
    maxLoan = ml;
    owesBank = 0.0;
    rate = r;
}

BrassPlus::BrassPlus(const Brass & ba, double ml, double r) : Brass(ba) //uses implicit copy constructor
{
    maxLoan = ml;
    owesBank = 0.0;
    rate = r;
}

//redefine how ViewAcct() works
void BrassPlus::ViewAcct(void) const
{
    //set up ###.## format
    format initialState = setFormat();
    precis prec = cout.precision(2);

    Brass::ViewAcct();  //display base portion
    cout << "Maxinum loan: $" << maxLoan << endl;
    cout << "Owed to bank: $" << owesBank << endl;
    cout .precision(3);
    cout << "Loan Rate : " << 100 * rate << "%" << endl;

    restore(initialState, prec);
}

//redefine how Withdraw() works
void BrassPlus::Withdraw(double amt)
{
    //set up ###.## format
    format initialState = setFormat();
    precis prec = cout.precision(2);

    double bal = Balance();
    if(amt <= bal)
    {
        Brass::Withdraw(amt);
    }
    else if(amt <= bal + maxLoan - owesBank)
    {
        double advance = amt - bal;
        owesBank += advance * (1.0 + rate);
        cout << "Bank advance: $" << advance << endl;
        cout << "Finance charge: $" << advance * rate << endl;

        Deposit(advance);
        Brass::Withdraw(amt);
    }
    else
    {
        cout << "Credit limit exceeded . Transaction cancelled." << endl;
    }

    restore(initialState, prec);
}

format setFormat(void)
{
    //set up ###.## format
    return cout.setf(std::ios_base::fixed, std::ios_base::floatfield);
}

void restore(format f, precis p)
{
    cout.setf(f, std::ios_base::floatfield);
    cout.precision(p);
}

#include <iostream>
#include <string>
#include "brass.h"
const int CLIENTS = 4;

int main(void)
{
    using std::cin;
    using std::cout;
    using std::endl;

    Brass * p_clients[CLIENTS];
    std::string temp;
    long tempnum;
    double tempbal;
    char kind;

    for(int i = 0; i < CLIENTS; i++)
    {
        cout << "Enter client's name: ";
        getline(cin, temp);
        cout << "Enter client's account number: ";
        cin >> tempnum;
        cout << "Enter opening balance: $";
        cin >> tempbal;
        cout << "Enter 1 for Brass Account or 2 for BrassPlus Account: ";

        while(cin >> kind && (kind != '1' && kind != '2'))
        {
            cout << "Enter either 1 or 2: ";
        }

        if(kind == '1')
        {
            p_clients[i] = new Brass(temp, tempnum, tempbal);
        }
        else
        {
            double tmax, trate;
            cout << "Enter the overdraft limit: $";
            cin >> tmax;
            cout << "Enter the interest rate " << "as a decimal fraction: ";
            cin >> trate;
            p_clients[i] = new BrassPlus(temp, tempnum, tempbal, tmax, trate);
        }

        while(cin.get() != '
')
        {
            continue;
        }
    }
    cout << endl;
    for(int i = 0; i < CLIENTS; i++)
    {
        p_clients[i]->ViewAcct();
        cout << endl;
    }

    for(int i = 0; i < CLIENTS; i++)
    {
        delete p_clients[i];
    }
    cout << "DONE.
";

    return 0;
}