Question

(C++)

How do I develop a polymorphic banking program using an already existing Bank-Account hierarchy? For each account in the vector, allow the user to specify an amount of money to withdraw from the Bank-Account using member function debit and an amount of money to deposit into the Bank-Account using member function credit. As you process each Bank-Account, determine its type. If a Bank-Account is a Savings, calculate the amount of interest owed to the Bank-Account using member function calculateInterest, then add the interest to the account balance using member function credit. After processing an account, print the updated account balance obtained by invoking base-class member function getBalance.

Here is the already existing code:

#include<iostream>

using namespace std;

//Define base class Bank_Account

class Bank_Account

{

protected:

       double balance; //data member to hold balance

public:

       //Parameterized constructor for initial balance

       Bank_Account(double bal)

       {

              //Check validity of balance

              if (bal >= 0)

              {

                     balance = bal;

              }

              else if (bal < 0)

              {

                     balance = 0;

                     cout << "\nInitial balance was invalid";

              }

       }

       //member function to credit the amount to account balance

       void credit(double amount)

       {

              balance = balance + amount;

       }

       //member function to debit amount from account balance

       bool debit(double amount)

       {

              //check if amount is valid

              if (amount > balance)

              {

                     cout << "\nThe balance is less than the debit amount";

                     return false;

              }

              else

              {

                     balance = balance - amount;

                     return true;

              }

       }

       //member function to fetch the acccount balance

       double getBalance()

       {

              return balance;

       }

};

//defined Savings_Account class with extending Bank_Account

class Savings_Account : public Bank_Account

{

protected:

       double interestRate;

public:

       //Parameterized constructor of Savings_Account which calls Parameterized constructor of Bank_Account with passing balance

       Savings_Account(double bal, double rate) :Bank_Account(bal)

       {

              interestRate = rate;

       }

       //member function to calculate interest rate  

       double calculateInterest()

       {

              return balance * interestRate;

       }

};

class Checking_Account : public Bank_Account

{

protected:

       double fee;

public:

       //Parameterized constructor of Checking_Account which calls Parameterized constructor of Bank_Account with passing balance

       Checking_Account(double bal, double feeTrans) :Bank_Account(bal)

       {

              fee = feeTrans;

       }

       //member function to apply transaction fee on crediting the amount

       void credit(double amount)

       {

              Bank_Account::credit(amount);

              balance = balance - fee;

       }

       //member function to apply transaction fee on debiting the amount

       void debit(double amount)

       {

              bool withdrawn = Bank_Account::debit(amount);

              if (withdrawn)

              {

                     balance = balance - fee;

              }

       }

};

int main()

{

       Bank_Account bankObj(200);

       Savings_Account savObj(300, 0.04);

       Checking_Account checkObj(400, 5.0);

       cout << endl << "Balance in Bank-Account: " << bankObj.getBalance();

       cout << endl << "Balance in Savings-Account: " << savObj.getBalance();

       cout << endl << "Balance in Checking-Account: " << checkObj.getBalance();

       bankObj.debit(50);

       savObj.debit(100);

       checkObj.debit(100);

       cout << endl << endl << "Balance after debiting amount from all three account";

       cout << endl << "Balance in Bank-Account: " << bankObj.getBalance();

       cout << endl << "Balance in Savings-Account: " << savObj.getBalance();

       cout << endl << "Balance in Checking-Account: " << checkObj.getBalance();

       bankObj.credit(100);

       savObj.credit(200);

       checkObj.credit(250);

       cout << endl << endl << "Balance after crediting amount from all three account";

       cout << endl << "Balance in Bank-Account: " << bankObj.getBalance();

       cout << endl << "Balance in Savings-Account: " << savObj.getBalance();

       cout << endl << "Balance in Checking-Account: " << checkObj.getBalance();

       double interestAmoutn = savObj.calculateInterest();

       savObj.credit(interestAmoutn);

       cout << endl << endl << "After adding interest, savings account have balance: " << savObj.getBalance();

       return 0;

}

Answer 1

Please go through instructions and comments carefully thank you

Add the following function in Savings_Account classs (at line 128 in code ) such that overwrites the parent class function.

virtual void credit(double amount)

{
//Calling parent functions from the derived function.
Bank_Account::credit(amount); //deposited balance
Bank_Account::credit(calculateInterest()); //deposited interest

}

virtual - keyword used to overwrite function

In the output credit is function used where balance deposited is 200 and including interest it is displayed as 416

Output for reference

128 //Functuon polymorpmsm techn飞que. us飞ng virtual void credit(double amount) 129 130 131 //Calling parent functions from the derived function. Bank_Account::credit (amount); Bank_Account::credit(calculateInterest)); //deposited interest 132 133 //deposited balance 134 135 136 137 138 input alance in Bank-Account: 200 Balance in Savings-Account: 300 Balance in Checking-Account: 400 Balance after debiting amount from all three account Balance in Bank-Account: 150 Balance in Savings-Account: 200 Balance in Checking-Account: 295 Balance after crediting amount from all three account Balance in Bank-Account: 250 Balance in Savings-Account: 416 Balance in Checking-Account: 540 ter adding interest, savings account have balance: 416