Two derived classes derived from the same base class have different results?

Two derived classes having same logic derived from same class but different results.

I have a base class named account and two derived classes from account class named savings_account and checking_account. When I make savings_account object, everything works fine, but when i make an object of checking_account class, it also creates an empty object account class. By using overloaded operator <<, cout << checking_account_object, it gives me the balance of checking_account_object. but when i use get_balance method, it gives me the balance of account_object (I created checking_Account_object but automatically created account_object). Similarly works with deposit method, it deposits money in account_object, not in checking_account_object. I have been stuck in this code for 2 days.

Here is my code for account class 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;
}

And Here is my code for savings_account

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;
}

and Here is checing_account class

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() function

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 is working well. But checking_account is not giving me required output. I expected the output of checking_account_object to be 48.5 The name of account is tanzeel and current balance is 48.5 but the output is -51.5 The name of account is tanzeel and current balance is 100