C++は自分の変数の1つを更新できません

Question

私はatmマシンを構築するためにこの学校の割り当てを受けました。私はそれが動作するようにしたが、私はお金を預金または引き出し、私の口座残高を見てもまだ更新されていない。誰かが私が間違ってやっていることを教えてもらえますか、私のコードを良くする方法についての提案は、一般に認められます。

#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(); 
} 

Answer 1

あなたは関数に渡す値を変更するだけです（したがって、関数の外で口座の残高を変更することはありません）。あなたがaccountbalanceを更新する必要があなたの方法のために、あなたのいずれかを行う必要があります参照

によって

• パスは、口座残高

てみてくださいを更新するために、戻り値を使用して、グローバル変数

を作成します。これらのうちの1つを見て、それがどうなるかを見てください。