C++在類之間傳遞對象

我確定我忽略了一些非常基本的東西。如果任何人都可以提供幫助，或者指向相關主題，我會非常感激。另外，如果你需要更多的代碼，我很樂意提供它。C++在類之間傳遞對象

我有一個簡單的銀行賬戶程序。在main（）類，我有以下功能：

void deposit(const Bank bank, ofstream &outfile) 
{ 
    int requested_account, index; 
    double amount_to_deposit; 
    const Account *account; 

    cout << endl << "Enter the account number: ";   //prompt for account number 
    cin >> requested_account; 

    index = findAccount(bank, requested_account); 
    if (index == -1)          //invalid account 
    { 
     outfile << endl << "Transaction Requested: Deposit" << endl; 
     outfile << "Error: Account number " << requested_account << " does not exist" << endl; 
    } 
    else             //valid account 
    { 
     cout << "Enter amount to deposit: ";    //prompt for amount to deposit 
     cin >> amount_to_deposit; 

     if (amount_to_deposit <= 0.00)      //invalid amount to deposit 
     { 
      outfile << endl << "Transaction Requested: Deposit" << endl; 
      outfile << "Account Number: " << requested_account << endl; 
      outfile << "Error: " << amount_to_deposit << " is an invalid amount" << endl; 
     } 
     else            //valid deposit 
     { 
      outfile << endl << "Transaction Requested: Deposit" << endl; 
      outfile << "Account Number: " << requested_account << endl; 
      outfile << "Old Balance: $" << bank.getAccount(index).getAccountBalance() << endl; 
      outfile << "Amount to Deposit: $" << amount_to_deposit << endl; 
      bank.getAccount(index).makeDeposit(&amount_to_deposit);  //make the deposit 
      outfile << "New Balance: $" << bank.getAccount(index).getAccountBalance() << endl; 
     } 
    } 
    return; 
} // close deposit()

的問題是與makeDeposit（& amount_to_deposit）。輸出文件顯示：

Transaction Requested: Deposit 
Account Number: 1234 
Old Balance: $1000.00 
Amount to Deposit: $168.00 
New Balance: $1000.00

在Account類，這裏是功能makeDeposit：

void Account::makeDeposit(double *deposit) 
{ 
    cout << "Account balance: " << accountBalance << endl; 
    accountBalance += (*deposit); 
    cout << "Running makeDeposit of " << *deposit << endl; 
    cout << "Account balance: " << accountBalance << endl; 
    return; 
}

控制檯輸出，從COUT電話，是：

Enter the account number: 1234 
Enter amount to deposit: 169 
Account balance: 1000 
Running makeDeposit of 169 
Account balance: 1169

所以，在makeDeposit（）函數中，它正確地更新了accountBalance變量。但是一旦函數結束，它就會恢復到初始值。

我相信這對於更有經驗的程序員來說是最基本的。非常感謝您的洞察力。

感謝，亞當

來源

2012-03-17 Adam_G

這是因爲你逝去的銀行按值而不是按引用和常量。更改

void deposit(const Bank bank, ofstream &outfile)

到

void deposit(Bank& bank, ofstream &outfile)

應該修復它

來源

2012-03-17 22:56:55

出於某種原因，仍然是沒有做的伎倆。然而，我看到大家都同意你的回答，這讓我覺得問題在我的最後。還有其他建議嗎？ – 2012-03-17 23:07:27

符合：bank.getAccount（index）是通過引用，指針或值返回的帳戶？ – 2012-03-17 23:10:17

我認爲這是通過引用返回的。這裏的實現： – 2012-03-17 23:14:45

C++在類之間傳遞對象

回答

相關問題