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;
} 

100 20 0.5
5 2

105.00
103.00
104.50
102.00
120.00

-10 20 8
10 93

Not a valid parameter.