Question

两个派生类，它们具有从同一个类派生的相同逻辑，但结果不同。

我有一个名为account的基类，还有两个从account类派生的名为savings_account和checking_account的派生类。当我制作savings_account对象时，一切正常，但是当我制作checking_account类的对象时，它也会创建一个空的对象account类。通过使用重载运算符<<，cout << checking_account_object，它为我带来了checking_account_object的余额。但是当我使用get_balance方法时，它给了我account_object余额（我创建了checking_Account_object但自动创建了account_object）。与deposit方法类似，它以account_object而不是checking_account_object存钱。我在此代码中停留了2天。

这是我的account类的代码：

class account
{
protected:
    string name;
    double balance;
public:
    friend ostream & operator << (ostream &out, account &bank);

    account(){
        name = "unknown";
        balance = 0.00;
    }
    account (const string &person_name, const double &person_balance){
        name = person_name;
        balance = person_balance;
    }
    bool deposit(const double &amount){
        if(amount <= 0)
            return false;
        else{
            balance += amount;
            return true;
        }
    }
    bool withdraw(const double &amount){
        if(amount <= 0 )
            return false;
        else{
            balance -= amount;
            return true;
        }
    }

    double getbalance(){
        return balance;
    }

};

ostream & operator << (ostream &out, account &bank){
    out << "The back balance of " << bank.name << " is " << bank.balance << endl;
    return out;
}

这是我的savings_account代码：

class savings_account : public account
{
protected:
    string name;
    double balance;
    double int_rate;

public:
    savings_account(){
        int_rate = 0;
        name = "unknown";
        balance = 0;
    }
    savings_account(const string &person_name, const double &person_balance, const double peronal_int_rate){
        int_rate = peronal_int_rate;
        name = person_name;
        balance = person_balance;
    }
    bool deposit(double amount){
        amount += (amount*int_rate)/100;
        return account::deposit(amount);
    }

    friend ostream & operator << (ostream &out, savings_account &bank);

};

ostream & operator << (ostream &out, savings_account &bank){
    out << "The bank balance of " << bank.name << " is " << bank.balance << endl;
    return out;
}

这是checing_account类：

class checking_account : public account{
protected:
    string name;
    double balance;
    const double fee = 1.5;

public:
    checking_account(){
        name  = "unknown";
        balance  = 0;
    }
    checking_account(const string &person_name, const double &personal_balance){
        name = person_name;
        balance = personal_balance;
    }
    bool withdraw(double amount){
        amount = amount + fee;
        return account::withdraw(amount);
    }

    friend ostream & operator << (ostream &out, checking_account &bank);
};

ostream & operator << (ostream &out, checking_account &bank){
    out << "The name of account is " << bank.name << " and current balance is " << bank.balance << endl;
    return out;
}

main()功能：

int main(){
    savings_account savings_account("tanzeel", 2000, 2);
    savings_account.deposit(1000);
    cout << savings_account.getbalance() << endl;
    savings_account.withdraw(100);
    cout << savings_account.getbalance() << endl;
    cout << savings_account;


    checking_account checking_account_object("tanzeel", 100.0);
    checking_account_object.deposit(50);;
    checking_account_object.withdraw(100);
    cout << checking_account_object.getbalance() << endl;
    cout << checking_account_object;

    return 0;
}

Savings_account运行良好。但是checking_account没有给我所需的输出。我期望checking_account_object的输出是

48.5
The name of account is tanzeel and current balance is 48.5

但是输出是 -51.5 帐户名为tanzeel，当前余额为100

从同一个基类派生的两个派生类有不同的结果？

0 个答案: