Classes

The BankAccount Class

//DISPLAY 10.5 The BankAccount Class 
//Program to demonstrate the class BankAccount.
#include <iostream>
using namespace std;

//Class for a bank account:
class BankAccount
{
public:
    void set(int dollars, int cents, double rate);
    //Postcondition: The account balance has been set to $dollars.cents;
    //The interest rate has been set to rate percent.

    void set(int dollars, double rate);
    //Postcondition: The account balance has been set to $dollars.00.
    //The interest rate has been set to rate percent.

    void update( );
    //Postcondition: One year of simple interest has been
    //added to the account balance.

    double get_balance( );
    //Returns the current account balance.

    double get_rate( );
    //Returns the current account interest rate as a percentage.

    void output(ostream& outs);
    //Precondition: If outs is a file output stream, then
    //outs has already been connected to a file.
    //Postcondition: Account balance and interest rate have  
    //been written to the stream outs.
private:
    double balance;
    double interest_rate;

    double fraction(double percent);
    //Converts a percentage to a fraction. For example, fraction(50.3) 
    //returns 0.503.
};

int main( )
{
    BankAccount account1, account2;
    cout << "Start of Test:\n";
    account1.set(123, 99, 3.0);
    cout << "account1 initial statement:\n";
    account1.output(cout);
    account1.set(100, 5.0);



cout << "account1 with new setup:\n";
    account1.output(cout);

    account1.update( );
    cout << "account1 after update:\n";
    account1.output(cout);

    account2 = account1;
    cout << "account2:\n";
    account2.output(cout);
    return 0;
}

void BankAccount::set(int dollars, int cents, double rate)
{
    if ((dollars < 0) || (cents < 0) || (rate < 0))
    {
        cout << "Illegal values for money or interest rate.\n";
    }

    balance = dollars + 0.01*cents;
    interest_rate = rate;
}

void BankAccount::set(int dollars, double rate)
{
    if ((dollars < 0) || (rate < 0))
    {
        cout << "Illegal values for money or interest rate.\n";
    }

    balance = dollars;
    interest_rate = rate;
}

void BankAccount::update( )
{
    balance = balance + fraction(interest_rate)*balance;
}

double BankAccount::fraction(double percent_value)
{
    return (percent_value/100.0);
}



double BankAccount::get_balance( )
{
    return balance;
}

double BankAccount::get_rate( )
{
    return interest_rate;
}

//Uses iostream:
void BankAccount::output(ostream& outs)
{
    outs.setf(ios::fixed);
    outs.setf(ios::showpoint);
    outs.precision(2);
    outs << "Account balance $" << balance << endl;
    outs << "Interest rate " << interest_rate << "%" << endl;
}

 

Alternative BankAccount Class Implementation

//DISPLAY 10.6 /Program to demonstrate the class BankAccount.
//Demonstrates an alternative implementation of the class BankAccount.
#include <iostream>
using namespace std;

//Class for a bank account:
class BankAccount
{
public:
    BankAccount(int dollars, int cents, double rate);
    //Initializes the account balance to $dollars.cents and
    //initializes the interest rate to rate percent.

    BankAccount(int dollars, double rate);
    //Initializes the account balance to $dollars.00 and
    //initializes the interest rate to rate percent.

    BankAccount( );
    //Initializes the account balance to $0.00 and the interest rate to 0.0%.

    void update( );
    //Postcondition: One year of simple interest has been added to the account 
    //balance.

    double get_balance( );
    //Returns the current account balance.

    double get_rate( );
    //Returns the current account interest rate as a percentage.

    void output(ostream& outs);
    //Precondition: If outs is a file output stream, then
    //outs has already been connected to a file.
    //Postcondition: Account balance and interest rate 
    //have been written to the stream outs.
private:
    double balance;
	double interest_rate;
	double fraction(double percent);
	//Converts a percentage to a fraction. For example, fraction(50.3)
	//returns 0.503.

};

int main( )
{
    BankAccount account1(100, 2.3), account2;

    cout << "account1 initialized as follows:\n";
    account1.output(cout);
    cout << "account2 initialized as follows:\n";
    account2.output(cout);

    account1 = BankAccount(999, 99, 5.5);
    cout << "account1 reset to the following:\n";
    account1.output(cout);
    return 0;
}

BankAccount::BankAccount(int dollars, int cents, double rate)
{
    if ((dollars < 0) || (cents < 0) || (rate < 0))
    {
        cout << "Illegal values for money or interest rate.\n";
    }
 	balance = dollars + 0.01*cents;
	interest_rate = rate;
}

BankAccount::BankAccount(int dollars, double rate)
{
	if ((dollars < 0) || (rate < 0))
	{
		cout << "Illegal values for money or interest rate.\n";
	}
	balance = dollars;
	interest_rate = rate;
}


BankAccount::BankAccount( )  : balance(0), interest_rate(0.0)
{
    //Body intentionally empty.
}

//Uses iostream:
void BankAccount::output(ostream& outs)
{
    outs.setf(ios::fixed);
    outs.setf(ios::showpoint);
    outs.precision(2);
    outs << "Account balance $" << balance << endl;
    outs << "Interest rate " << interest_rate << "%" << endl;
}



 

Alternative BankAccount Class Implementation

//DISPLAY 10.7 Alternative BankAccount Class Implementation
//Demonstrates an alternative implementation of the class BankAccount.
#include <iostream>
#include <cmath>
using namespace std;

//Class for a bank account:
class BankAccount
{
public:
    BankAccount(int dollars, int cents, double rate);
    //Initializes the account balance to $dollars.cents and
    //initializes the interest rate to rate percent.

    BankAccount(int dollars, double rate);
    //Initializes the account balance to $dollars.00 and
    //initializes the interest rate to rate percent.

    BankAccount( );
    //Initializes the account balance to $0.00 and the interest rate to 0.0%.

    void update( );
    //Postcondition: One year of simple interest has been added to the account 
    //balance.

    double get_balance( );
    //Returns the current account balance.

    double get_rate( );
    //Returns the current account interest rate as a percentage.

    void output(ostream& outs);
    //Precondition: If outs is a file output stream, then
    //outs has already been connected to a file.
    //Postcondition: Account balance and interest rate 
    //have been written to the stream outs.
private:
    int dollars_part;
    int cents_part;
    double interest_rate;//expressed as a fraction, for example, 0.057 for 5.7%

    double fraction(double percent);
    //Converts a percentage to a fraction. For example, fraction(50.3) 
    //returns 0.503.

    double percent(double fraction_value);
    //Converts a fraction to a percentage. For example, percent(0.503)
    //returns 50.3.
};

int main( )
{
    BankAccount account1(100, 2.3), account2;

    cout << "account1 initialized as follows:\n";
    account1.output(cout);
    cout << "account2 initialized as follows:\n";
    account2.output(cout);

    account1 = BankAccount(999, 99, 5.5);
    cout << "account1 reset to the following:\n";
    account1.output(cout);
    return 0;
}

BankAccount::BankAccount(int dollars, int cents, double rate)
{
    if ((dollars < 0) || (cents < 0) || (rate < 0))
    {
        cout << "Illegal values for money or interest rate.\n";
    }
    dollars_part = dollars;
    cents_part = cents;
    interest_rate = fraction(rate);
}

BankAccount::BankAccount(int dollars, double rate)
{
    if ((dollars < 0) || (rate < 0))
    {
        cout << "Illegal values for money or interest rate.\n";
    }
    dollars_part = dollars;
    cents_part = 0;
    interest_rate = fraction(rate);
}

BankAccount::BankAccount( ) : dollars_part(0), cents_part(0), interest_rate(0.0)
{
    //Body intentionally empty.
}


double BankAccount::fraction(double percent_value)
{
    return (percent_value/100.0);
}

//Uses cmath:
void BankAccount::update( )
{
    double balance = get_balance( );
    balance = balance + interest_rate*balance;
    dollars_part = floor(balance);
    cents_part = floor((balance - dollars_part)*100);
}

double BankAccount::get_balance( )
{
    return (dollars_part + 0.01*cents_part);
}

double BankAccount::percent(double fraction_value)
{
    return (fraction_value*100);
}

double BankAccount::get_rate( )
{
    return percent(interest_rate);
}

//Uses iostream:
void BankAccount::output(ostream& outs)
{
    outs.setf(ios::fixed);
    outs.setf(ios::showpoint);
    outs.precision(2);
    outs << "Account balance $" << get_balance( ) << endl;
    outs << "Interest rate " << get_rate( ) << "%" << endl;
}

 




 
Topic revision: r1 - 2015-11-09 - JimSkon
 
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