Sample Program: Inheritance Hierarchy of Bank Accounts with Polymorphic Print Functions
//////////////////////////////////////////////////////////////////////
// this program uses an inheritance hierarchy of bank accounts.
//
// this version has base and derived class constructors
// and virtual print functions to demonstrate polymorphism
//////////////////////////////////////////////////////////////////////
#include <iostream.h>
#include <iomanip.h>
//////////////////////////////////////////////////////////////////////
// class BankAccount
// this is the abstract base class for all types of bank accounts
// it has the following member functions
// deposit() make deposit into account
// account_num() access the account number
// balance() access the account balance
// print() pure virtual function to print data members
// it has the following data members
// acctnum the account number
// bal the amount of money in the account
//////////////////////////////////////////////////////////////////////
class BankAccount
{
public:
BankAccount(int=0,float=0);
void deposit(float amount) { bal += amount; }
int account_num() const { return acctnum; }
float balance() const { return bal; }
virtual void print() = 0;
protected:
int acctnum;
float bal;
};
//////////////////////////////////////////////////////////////////////
// constructor for BankAccounts; both args can default to zero
BankAccount::BankAccount(int num, float ibal)
{
acctnum = num;
bal = ibal;
}
//////////////////////////////////////////////////////////////////////
// class Checking
// this class is derived from BankAccount; it represents checking accounts
// it contains the following additional member functions
// Checking() constructor
// cash_check() cash check and debit balance
// print() virtual function to print data members
// it contains the following additional data members
// minimum per check charge added if bal < minbal
// charge amount charged per check when bal < minbal
//////////////////////////////////////////////////////////////////////
class Checking : public BankAccount
{
public:
Checking(int=0,float=0,float=1000,float=.25);
int cash_check(float);
virtual void print();
protected:
float minimum;
float charge;
};
//////////////////////////////////////////////////////////////////////
// constructor for checking accounts -- all parms can default
Checking::Checking(int num, float ibal, float min, float chg)
: BankAccount(num,ibal)
{
minimum = min;
charge = chg;
}
//////////////////////////////////////////////////////////////////////
// cash a check
// return false if there is not enough money to cash the check
// otherwise cash the check, deduct per check fee if below
// the minimum balance
int Checking::cash_check(float amount)
{
char pause;
// check for insufficient funds, write message and exit false
if (amount >= bal)
{
cout << endl << "Cannot cash check for $" << amount << " on account "
<< acctnum << "; insufficient funds." << endl;
cout << "Press enter to continue." << endl;
cin.get(pause);
return 0;
}
// cash check and deduct per check charge if necessary
if (bal < minimum)
bal -= amount + charge;
else
bal -= amount;
return 1;
}
///////////////////////////////////////////////////////////////////////
// virtual print function for Checking
void Checking::print()
{
cout << "Checking Account: " << acctnum << endl;
cout << "\tBalance: " << bal << endl;
cout << "\tMinimum to Avoid Charges: " << minimum << endl;
cout << "\tCharge per Check: " << charge << endl << endl;
}
//////////////////////////////////////////////////////////////////////
// class InterestChecking
// this class is derived from Checking; it represents interest
// bearing checking accounts
// it contains the following additional member functions
// InterestChecking() constructor
// interest() calculate and add interest if bal > minbal
// print() virtual function to print data members
// it contains the following additional data members
// intrate annual interest rate earned when bal > minbal
// credited monthly
// minint minimum balance required to receive interest
// moncharge monthly fee (only charged if minimum balance
// not met)
//////////////////////////////////////////////////////////////////////
class InterestChecking : public Checking
{
public:
InterestChecking(int=0,float=0,float=1000,float=2500,float=.25,
float=2.5,float=10);
void interest();
virtual void print();
protected:
float intrate;
float minint;
float moncharge;
};
//////////////////////////////////////////////////////////////////////
// constructor for InterestChecking accounts -- all parms can default
InterestChecking::InterestChecking(int num, float ibal, float cmin, float imin,
float chg, float rate, float monchg) : Checking(num,ibal,cmin,chg)
{
intrate = rate;
minint = imin;
moncharge = monchg;
}
//////////////////////////////////////////////////////////////////////
// add interest to InterestChecking account -- interest is earned
// only when balance is above the minimum; if not, the monthly fee is charged
void InterestChecking::interest()
{
const int nummths = 12;
const int cvtpct = 100;
if (bal >= minint)
{
float intamt = bal * intrate / (nummths * cvtpct);
bal += intamt;
}
else
bal -= moncharge;
}
///////////////////////////////////////////////////////////////////////
// virtual print function for InterestChecking
void InterestChecking::print()
{
cout << "Interest Checking Account: " << acctnum << endl;
cout << "\tBalance: " << bal << endl;
cout << "\tMinimum to Avoid Charges: " << minimum << endl;
cout << "\tCharge per Check: " << charge << endl;
cout << "\tMinimum for Interest and No Monthly Fee: " << minint << endl;
cout << "\tInterest: " << intrate << "%" << endl;
cout << "\tMonthly Fee: " << moncharge
<< "\n\n";
}
//////////////////////////////////////////////////////////////////////
// class Savings
// this class is derived from BankAccount; it represents savings accounts
// it contains the following additional member functions
// Savings() constructor
// interest() caculate and add interest
// withdraw() debit account for a withdrawal
// print() virtual function to print data members
// it contains the following additional data members
// intrate annual interest rate earned
// credited monthly
//////////////////////////////////////////////////////////////////////
class Savings : public BankAccount
{
public:
Savings(int=0,float=0,float = 3.5);
void interest();
int withdraw(float);
virtual void print();
protected:
float intrate;
};
//////////////////////////////////////////////////////////////////////
// constructor for savings accounts -- all parms can default
Savings::Savings(int num, float ibal, float rate) : BankAccount(num,ibal)
{
intrate = rate;
}
//////////////////////////////////////////////////////////////////////
// withdraw from a Savings account -- returns false if the withdrawal
// was not done because of insufficient funds; otherwise return true
int Savings::withdraw(float amount)
{
char pause;
if (bal <= amount)
{
cout << endl << "Withdrawal of $" << amount << " from account "
<< acctnum << " not permitted; insufficient funds." << endl;
cout << endl << "Press Enter to continue." << endl;
cin.get(pause);
return 0;
}
bal -= amount;
return 1;
}
//////////////////////////////////////////////////////////////////////
// add interest to a savings account
void Savings::interest()
{
const int nummths = 12;
const int cvtpct = 100;
float intamt = bal * intrate / (nummths * cvtpct);
bal += intamt;
}
///////////////////////////////////////////////////////////////////////
// virtual print function for Savings
void Savings::print()
{
cout << "Savings Account: " << acctnum << endl;
cout << "\tBalance: " << bal << endl;
cout << "\tInterest: " << intrate << "%" << endl << endl;
}
//////////////////////////////////////////////////////////////////////
// main program to test our classes
void main()
{
BankAccount * accounts[4];
// define bank accounts
Checking stroustrup(1001,750);
InterestChecking thompson(1005,3500);
Savings kernighan(1022,1000);
Checking ritchie(1014,600);
accounts[0] = &stroustrup;
accounts[1] = &thompson;
accounts[2] = &kernighan;
accounts[3] = &ritchie;
// set up output for dollar amounts
cout.setf(ios::fixed,ios::floatfield);
cout.setf(ios::showpoint);
cout << setprecision(2);
// checking account transactions
stroustrup.deposit(1500);
stroustrup.cash_check(250);
stroustrup.cash_check(195.99);
stroustrup.cash_check(650);
stroustrup.cash_check(1195);
ritchie.cash_check(125.50);
ritchie.deposit(1200);
ritchie.cash_check(369.99);
// interest checking account transactions
thompson.cash_check(365.55);
thompson.deposit(965);
// savings account transactions
kernighan.withdraw(450);
kernighan.deposit(300);
kernighan.withdraw(400);
// add interest where appropriate
thompson.interest();
kernighan.interest();
// report on account balances
cout << endl << endl << "\t\tAccount Balances" << endl << endl;
cout << endl << "Account Number: " << stroustrup.account_num();
cout << " Balance: $ " << stroustrup.balance() << endl;
cout << endl << "Account Number: " << kernighan.account_num();
cout << " Balance: $ " << kernighan.balance() << endl;
cout << endl << "Account Number: " << thompson.account_num();
cout << " Balance: $ " << thompson.balance() << endl;
cout << endl << "Account Number: " << ritchie.account_num();
cout << " Balance: $ " << ritchie.balance() << endl;
cout << endl;
for (int i = 0 ; i < 4 ; i++)
accounts[i]->print();
}
Output
Cannot cash check for $1195.00 on account 1001; insufficient funds.
Press enter to continue.
Account Balances
Account Number: 1001 Balance: $ 1154.01
Account Number: 1022 Balance: $ 451.31
Account Number: 1005 Balance: $ 4107.99
Account Number: 1014 Balance: $ 1304.26
Checking Account: 1001
Balance: 1154.01
Minimum to Avoid Charges: 1000.00
Charge per Check: 0.25
Interest Checking Account: 1005
Balance: 4107.99
Minimum to Avoid Charges: 1000.00
Charge per Check: 0.25
Minimum for Interest and No Monthly Fee: 2500.00
Interest: 2.50%
Monthly Fee: 10.00
Savings Account: 1022
Balance: 451.31
Interest: 3.50%
Checking Account: 1014
Balance: 1304.26
Minimum to Avoid Charges: 1000.00
Charge per Check: 0.25
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