Question

我确定我忽略了一些非常基本的东西。如果有人可以提供一些帮助，或者指出我的相关主题，我将非常感激。此外，如果您需要更多我的代码，我很乐意提供它。

我有一个简单的银行账户计划。在main（）类中，我有以下函数：

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()

问题在于makeDeposit（＆amp; amount_to_deposit）。输出文件显示：

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

在Account类中，这是函数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;
}

来自cout调用的控制台输出是：

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

因此，在makeDeposit（）函数中，它正确地更新了accountBalance变量。但是一旦函数结束，它就会恢复到初始值。

我确信这对于经验丰富的程序员来说非常重要。非常感谢您的见解。

谢谢，亚当

Answer 1

这是因为你通过值传递Bank而不是通过引用和const。改变

void deposit(const Bank bank, ofstream &outfile)

到

void deposit(Bank& bank, ofstream &outfile)

应该解决它

C ++在类之间发出传递对象的问题

1 个答案: