如何使方法更新C++中的类的属性

我想对银行中不同类型的账户进行一些基本的模拟。我已经创建了一个类Account，Savings_Account&Checking_Account是一个AccountandTrust_Account是一个Savings_Account. 我只在Account课堂上有问题，所以这个问题只会集中在Account课堂上。我在Account班级中只有两个属性：std::string name和double balance. 我在Account课堂上也有两个方法：bool deposit(double amount)和bool withdraw(double amount)。问题：当我deposit(amount)工作正常并更新balance时，但当我withdraw(amount)更新时balance没有反映并amount退出默认余额。

我的代码：

帐户.hpp

#pragma once
#include
#include
#include
using std::cout;
using std::cin;
using std::endl;
using std::string;
using std::vector;
//The Account class(parent class)
class Account{
friend std::ostream &operator<<(std::ostream &os, const Account &account); //Outputs the object
private:
static constexpr const char *def_name = "Empty"; //Default name
static constexpr double def_balance = 0.0; //Default balance
protected:
string name{}; //Name of the Account holder
double balance{}; //Balance of the Account
public:
Account(string n = def_name, double b = def_balance); //Constructor
bool deposit(double amount); //Method to deposit
bool withdraw(double amount); //Method to withdraw
};


帐户.cpp

#include "Accounts.hpp"
//Construtor
Account::Account(string n, double b)
:name{n}, balance{b} {
}
//Method for deposit
bool Account::deposit(double amount) {
if (amount <0)
return false;
else {
balance += amount;
return true;
}
}
//Method for withdraw
bool Account::withdraw(double amount) {
if (balance - amount >= 0) {
balance -= amount;
return true;
} else {
return false;
}
}
//Outputs the object
std::ostream &operator<<(std::ostream &os, const Account &account) {
os <<"A-> " < return os;
}


我也做了一些实用功能，让我display，deposit以及withdraw所有Account在vector acnt

AccountsUtil.hpp

#include "Accounts.hpp"
/* Util functions for Account */
//Displays all the Account
void display(const vector &a);
//Deposits to all the Account
void deposit(vector &a, double bl);
//Withdraws from all the Account
void withdraw(vector &a, double bl);


AccountsUtil.cpp

/* Utils for Account */
//Displays all the Account
void display(const vector &a) {
cout <<"--->Accounts----------------" < for (const auto &i: a)
cout < cout <<"=====================================n" <}
//Deposits to all the Account
void deposit(vector &a, double bl) {
cout <<"Depositing for Account=========================" < for (auto i: a) {
if (i.deposit(bl))
cout <<"Deposit successful for:=> " < else
cout <<"Deposit failed for:=> " < }
cout <<"==============================================n" <}
//Withdraws from all the Account
void withdraw(vector &a, double bl) {
cout <<"Withdrawing for Account============================" < for (auto i: a) {
if (i.withdraw(bl))
cout <<"Withdraw successful for :=> " < else
cout <<"Withdraw failed for :=> " < }
cout <<"===================================================n" <}


主程序

#include "AccountsUtil.hpp"
int main() {
vector acnt;
acnt.push_back(Account {});
acnt.push_back(Account {"Tony"});
acnt.push_back(Account {"Steve", 2000});
acnt.push_back(Account {"Thor", 5000});
display(acnt);
deposit(acnt,1000);
withdraw(acnt,3000);
return 0;
}


我的输出（错误/意外）

--->Accounts----------------
A-> Empty : 0
A-> Tony : 0
A-> Steve : 2000
A-> Thor : 5000
=====================================
Depositing for Account=========================
Deposit successful for:=> A-> Empty : 1000
Deposit successful for:=> A-> Tony : 1000
Deposit successful for:=> A-> Steve : 3000
Deposit successful for:=> A-> Thor : 6000
==============================================
Withdrawing for Account============================
Withdraw failed for :=> A-> Empty : 0
Withdraw failed for :=> A-> Tony : 0
Withdraw failed for :=> A-> Steve : 2000
Withdraw successful for :=> A-> Thor : 2000
===================================================


很明显，存款时余额已更新，但在提取时使用了默认余额。例如：在存入史蒂夫的余额为 3000 后，因此从史蒂夫那里提取 3000 应该可以正常工作，但对他而言提取失败表明他只有 2000，这是他的默认余额。我怎么解决这个问题？谢谢。