C++ C++；can'；t更新我的一个变量

我有一个学校的任务是制造一台自动取款机。我让它工作，但如果我存款或取款，并查看我的帐户余额后，它仍然没有更新。如果有人能告诉我我做错了什么，并且对如何改进我的代码提出建议，我将不胜感激

#include <iostream>
#include <fstream>
#include <string>
#include <cmath>
using namespace std;

void WelcomeMenu();
void Menu();
void userChoiceDeposite(double accountbalance);
void userChoiceWithdraw(double accountbalance);
void userChoiceView(double accountbalance);
void printReceipt();


int main ()
{
//clear receipt.txt from previous transactions
ofstream clearFile("Receipt.txt");
clearFile.close();


//Declaring variables
string userInput;
char userAction;

//prompt user for input, start the program or quit
cout <<"Enter start to continue, or Q/q to quit ";
getline (cin, userInput);
cout <<endl;

//check the input
if ((userInput == "q") || (userInput == "Q"))
{
    cout <<"Have a nice day!" <<endl;
    return 0;
}

else if (userInput == "start")
{
const int sizeLimit = 50;
string firstName[sizeLimit], lastName[sizeLimit], passWord[sizeLimit];
double accountBalance[sizeLimit];
int count = 0;

ifstream readFile("Accounts.txt");

 while (!readFile.eof())
 {
    readFile >> firstName[count];
    readFile >> lastName[count];
    readFile >> passWord[count];
    readFile >> accountBalance[count];
    count++;
 }
    //ask for username/pw
    string fName, lName, pwd;
    double accountbalance;
    bool exists = false;

 do
 {
    cout <<"Enter First Name: ";
    cin >> fName;
    cout <<"Enter Last Name: ";
    cin >>lName;
    cout <<"Enter Password: ";
    cin >> pwd;

    for (int i=0; i<sizeLimit; i++)
    {
        if (firstName[i] == fName)
        {
            if (lastName[i] == lName)
            {
                if (passWord[i] == pwd)
                {
                    exists = true;
                    accountbalance = accountBalance[i];
                }
            }
        }
    }
 }
 while (exists == false);
    //if correct display menu
    WelcomeMenu();
    cin >> userAction;
    //while login is valid (true)
    while (userAction != 'q')
    {


        if (userAction == 'D' || userAction == 'd')
        {
            userChoiceDeposite(accountbalance);
        }
        else if (userAction == 'W' || userAction == 'w')
        {
            userChoiceWithdraw(accountbalance);
        }
        else if (userAction == 'V' || userAction == 'v')
        {
            userChoiceView(accountbalance);
        }
        else if (userAction == 'P' || userAction == 'p')
        {
            printReceipt();
            return 0;
        }
        else
        {
            cout <<"Have a nice Day" <<endl;
            return 0;
        }
        Menu();
        cin >> userAction;


    }
}

else
{
    cout <<"Input Error..." <<endl;
}


return 0;
}


//welcome menu display function
void WelcomeMenu()
{

cout <<"Welcome to your account " <<endl;
cout <<endl;
cout <<"[D/d] Deposit Money" <<endl;
cout <<"[W/w] Withdraw Money" <<endl;
cout <<"[V/v] View Account Balance" <<endl;
cout <<"[Q/q] Quit" <<endl;

}
//function after action was taken (add print option)
void Menu()
{
cout <<endl;
cout <<"[D/d] Deposit Money" <<endl;
cout <<"[W/w] Withdraw Money" <<endl;
cout <<"[V/v] View Account Balance" <<endl;
cout <<"[P/p] Print Receipt and quit" <<endl;
cout <<"[Q/q] Quit" <<endl;

}
//deposit function
void userChoiceDeposite(double accountbalance)
{

int depositMoney;
cout <<"Enter the ammount of money you want to deposit. Max $10000"         <<endl;
cin >> depositMoney;

if ((depositMoney > 0) && (depositMoney <= 10000))
{
    accountbalance = accountbalance + depositMoney;
    ofstream saveAction("Receipt.txt", ios_base::app);
    saveAction << "You made a deposit of $" <<depositMoney <<endl;
    saveAction.close();

}
else
{
    cout <<"Incorrect ammount" <<endl;
    return userChoiceDeposite(1);
}

}
//withdraw function
void userChoiceWithdraw(double accountbalance)
{
int withdrawMoney;
cout <<"Enter the ammount of $ you want to withdraw:";
cin >> withdrawMoney;

if (accountbalance < withdrawMoney)
{
    cout <<"You dont have that much money"<<endl;
    return userChoiceWithdraw(1);
}
else
{
    accountbalance = accountbalance - withdrawMoney;
    ofstream saveAction("Receipt.txt", ios_base::app);
    saveAction << "You withdrew $" <<withdrawMoney <<endl;
    saveAction.close();
}
}
//view function
void userChoiceView(double accountbalance)
{
cout <<"Your account balance is $" <<accountbalance <<endl;
ofstream saveAction("Receipt.txt", ios_base::app);
saveAction << "You viewed your account balance" <<endl;
saveAction.close();


}
//print receipt function
void printReceipt()
{
ofstream saveAction("Receipt.txt", ios_base::app);
saveAction << "" <<endl;
saveAction << "" <<endl;
saveAction << "" <<endl;
saveAction << "Thank you! Come again!" <<endl;
saveAction.close();
}

#包括
#包括
#包括
#包括
使用名称空间std；
void WelcomeMenu（）；
无效菜单（）；
作废用户选择存储（双倍账户余额）；
作废用户选择取款（双倍账户余额）；
作废用户选择视图（双倍账户余额）；
作废打印收据（）；
int main（）
{
//从以前的交易中清除receive.txt
流clearFile（“Receipt.txt”）；
clearFile.close（）；
//声明变量
字符串用户输入；
字符用户行为；
//提示用户输入、启动程序或退出
会计科目余额[计数]；
计数++；
}
//询问用户名/pw
字符串fName，lName，pwd；
双重账户余额；
bool exists=false；
做
{
cout fName；
名称；
cout-pwd；
对于（inti=0；i>userAction；
//登录有效时（true）
while（userAction！=“q”）
{
if（userAction='D'| | userAction=='D'）
{
userChoiceDeposite（账户余额）；
}
else if（userAction='W'| | userAction=='W'）
{
用户选择取款（账户余额）；
}
else if（userAction='V'| | userAction=='V'）
{
用户选择视图（账户余额）；
}
else if（userAction=='P'| | userAction=='P'）
{
打印收据（）；
返回0；
}
其他的
{
cout您只更改传递到函数中的值（因此不会更改函数外部的accountbalance）。对于需要更新accountbalance的方法，您需要：


参照
创建一个全局变量
使用返回值更新帐户余额

试一下其中的一个。< /P>相关/ DUPE：也值得阅读：考虑替换<代码>（Read Fixe>FrestNoth[Cal]）> LSTNEST[计数] >密码[计数] > ActualStale[计数] {{C++}；}。

这利用了

>

返回对输入流的引用，从而允许IO链接和可能的重复