我的题解
该题难度较低,我发个压行代码

#include<iostream>
#include<iomanip>
#include<string>
using namespace std;

class Account
{
protected:
    double balance;
public:
    void setBalance(double v) { balance = v; }
    double getBalance() { return balance; }
    Account(double v = 0.0) :balance(v){}
    void credit(double val) { balance += val; }
    bool debit(double val) {
        if (balance >= val) return (balance -= val, true);
        else return (cout << "Debit amount exceeded account balance.\n",false);
    }
    bool check() { return balance >= 0; }
};

class CheckingAccount : public Account
{
private:
    double ff;
public:
    CheckingAccount(double v=0.0, double f=0.0) : ff(f) { balance = v; }
    bool credit(double v) {
        if (balance + v - ff >= 0) return (balance += v - ff, true);
        else return (cout << "Operation not permitted.\n",false);
    }
    bool debit(double v) {
        if (balance >= v + ff) return balance -= v + ff, true;
        else return (cout << "Operation not permitted.\n",false);
    }
};

class SavingAccount : public Account
{
private:
    double ra;
public:
    SavingAccount(double v, double r) :ra(r) { balance = v; }
    using Account::credit;
    using Account::debit;
    double calculateInterest() { return balance * ra; }
};

int main() {
    //初始化 
    //输入账户余额 
    double balance;
    cin >> balance;
    //创建一个Account实例 
    Account a(balance);
    //检查输入的balance是否合法 
    if (!a.check()) {
        a.setBalance(0);
        cout << "Not a valid parameter." << endl;
        return 0;
    }

    //输入利率 
    double rate;
    cin >> rate;
    //创建一个SavingAccount实例 
    SavingAccount aSaving(balance, rate);

    //输入手续费
    double fee;
    cin >> fee;
    //创建一个 CheckingAccount实例 
    CheckingAccount aChecking(balance, fee);

    //模拟业务 
        //输入存取钱数 
    double creditAmount;
    double debitAmount;
    cin >> creditAmount >> debitAmount;
    //测试Acount 
    a.credit(creditAmount); //存钱 
    cout << fixed << setprecision(2) << a.getBalance() << endl;//输出余额 
    if (a.debit(debitAmount)) { // 取钱 
        cout << fixed << setprecision(2) << a.getBalance() << endl;// 输出余额
    }
    // 测试 CheckingAccount
    if (aChecking.credit(creditAmount)) {
        cout << fixed << setprecision(2) << aChecking.getBalance() << endl;
    }

    if (aChecking.debit(debitAmount)) {
        cout << fixed << setprecision(2) << aChecking.getBalance() << endl;
    }
    //测试 SavingAccount
    double interest = aSaving.calculateInterest();
    aSaving.credit(interest);
    cout << fixed << setprecision(2) << aSaving.getBalance() << endl;

    return 0;
}