帮助处理类和派生类

我正在处理一个使用基类"bankAccount"和两个派生类"checkingAccount"answers"savingsAccount"的分配。我现在对我得到的输出感到困惑。所有期末余额都是负的。谁能看看我的代码，看看他们是否发现这可能是为什么?我认为我在派生类"checkingAccount"的过程函数中做错了什么。"savingsAccount"过程函数将是类似的，我只是还没有做，因为第一个不工作。谢谢!

#ifndef HEADER_H_INCLUDED
#define HEADER_H_INCLUDED
#include <iostream>
#include <fstream>

using namespace std;
class bankAccount
{
    public:
    bankAccount();
    void setAccountInfo(int accountNumTemp, double balanceTemp);
    void prePrint(char accountType);
    void process(char accountType, char transactionTypeTemp, int amountTemp, int j);
    void postPrint();
    private:
    int accountNumber;
    double balance;
};
class checkingAccount: public bankAccount
{
    public:
    void prePrint(int accountNumber, char accountType, double checkingBalance);
    checkingAccount();
    double checkingAccount:: process(char transactionTypeTemp, int amountTemp, int j, double checkingBalance);
    /*applyTansaction();
    applyInterest();*/
    private:
    float interestRate;
    int minimumBalance;
    float serviceCharge;
};
class savingsAccount: public bankAccount
{
    public:
    void prePrint(int savingsAccountNumber, char accountType, double savingsBalance);
    savingsAccount();
   /* applyTansaction();
    applyInterest();*/
    private:
    float interestRate;
};

#endif // HEADER_H_INCLUDED

类实现:

#include "header.h"
bankAccount:: bankAccount()
{
    accountNumber = 0;
    balance = 0;
}
void bankAccount:: setAccountInfo(int accountNumTemp, double balanceTemp)
{
    accountNumber = accountNumTemp;
    balance = balanceTemp;
}
void bankAccount:: prePrint(char accountType)
{
    if(accountType == 'C')
    {
        int checkingAccountNumber = accountNumber;
        double checkingBalance = balance;
        checkingAccount ca;
        ca.prePrint(checkingAccountNumber, accountType, checkingBalance);
    }
    else if (accountType == 'S')
    {
        int savingsAccountNumber = accountNumber;
        double savingsBalance = balance;
        savingsAccount sa;
        sa.prePrint(savingsAccountNumber, accountType, savingsBalance);
    }

}
void bankAccount:: process(char accountType, char transactionTypeTemp, int amountTemp, int j)
{
        double checkingBalance;
        checkingAccount ca;
        //savingsAccount sa;
        if (accountType == 'C')
        {
            checkingBalance = balance;
            balance = ca.process(transactionTypeTemp, amountTemp, j, checkingBalance);
        }
        /*else if (accountType == 'S')
        {
            savingsBalance = balance;
            sa.process(transactionTypeTemp, amountTemp, j, savingsBalance)
        }*/
}
void bankAccount:: postPrint()
{
   cout << "Balance after processing: " << balance << endl;
}
checkingAccount:: checkingAccount()
{
    interestRate = .02;
    minimumBalance = 500;
    serviceCharge = 20;
}
void checkingAccount:: prePrint(int checkingAccountNumber, char accountType, double checkingBalance)
{
    cout << "Account Number:" << checkingAccountNumber << " account type:" << accountType << " Starting Balance:" << checkingBalance << endl;
}
double checkingAccount:: process(char transactionTypeTemp, int amountTemp, int j, double checkingBalance)
{
  if (transactionTypeTemp == 'D')
        {
            checkingBalance = checkingBalance + amountTemp;
            checkingBalance = (checkingBalance * interestRate);
        }
  else if (transactionTypeTemp == 'W')
        {
            if ((checkingBalance = checkingBalance - amountTemp) < 0)
            {
            cout << "error: transaction number" << j + 1 << " never occured due to insufficent funds." << endl;
            }
            else
            {
                checkingBalance = checkingBalance - amountTemp;
                if(checkingBalance < minimumBalance) //if last transaction brought the balance below minimum balance
                {
                    checkingBalance = (checkingBalance - serviceCharge); //apply service charge
                    checkingBalance = (checkingBalance * interestRate);  //apply interest
                }
                else // if last transaction did not bring the balance below minimum balance
                {
                    checkingBalance = (checkingBalance * interestRate); //apply interest without service charge
                }
            }
        }
        return checkingBalance;
}
savingsAccount:: savingsAccount()
{
    interestRate = .04;
}
void savingsAccount:: prePrint(int savingsAccountNumber, char accountType, double savingsBalance)
{
    cout << "Account Number:" << savingsAccountNumber << " account type:" << accountType << " Starting Balance:" << savingsBalance << endl;
}

#include "header.h"
int main()
{
    ifstream inFile;
    int numberOfAccounts, accountNumTemp, transactionNum, amountTemp;
    double balanceTemp;
    char discard, accountType, transactionTypeTemp;
    bankAccount ba;
    cout << "Processing account data..." << endl;
    inFile.open("Bank.txt");
    if (!inFile)
    {
        for  (int a = 0; a < 20; a++)
            cout  << endl;
        cout << "Cannot open the input file."
             << endl;
            return 1;
    }
    inFile >> numberOfAccounts;
    inFile.get(discard);
    for (int i = 0; i < numberOfAccounts; i++)
    {
            inFile >> accountNumTemp >> accountType >> balanceTemp >> transactionNum;
            inFile.get(discard);
            ba.setAccountInfo(accountNumTemp, balanceTemp);
            ba.prePrint(accountType);
            for (int j = 0; j < transactionNum; j++)
            {
                inFile >> transactionTypeTemp >> amountTemp;
                inFile.get(discard);
                ba.process(accountType, transactionTypeTemp, amountTemp, j);
            }
            ba.postPrint();
    }

    inFile.close();
    return 0;
}