Difference: Lab7Startup (1 vs. 2)

Revision 22018-03-28 - JimSkon

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META TOPICPARENT name="Fall2017"
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Classes and Objects Example

%CODE{"c++"}% //DISPLAY 10.6 /Program to demonstrate the class BankAccount. //Demonstrates an alternative implementation of the class BankAccount. #include using namespace std;
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Classes and Objects with friends

Goal

 
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//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; }

%ENDCODE%

Start Project 7

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Enhance Date function with friend and operator methods

Steps

  1. Start with the Date class developed previously in class. A copy is here : DateClass
  2. Add a friend function "bool Equals(Date a, Date b)" that returns true if the dates are equal
  3. Add a friend function "Date Add(Date d, int i) " that adds an integer i days to Date, and returns that date.
  4. Add a operator "==" if the two are equal.
  5. Add a "+" opperator that adds Date with an integer: d2 = d1 + 16;

Revision 12017-10-23 - JimSkon

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META TOPICPARENT name="Fall2017"

Classes and Objects Example

<-- SyntaxHighlightingPlugin -->
//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;
}
 
<-- end SyntaxHighlightingPlugin -->

Start Project 7

 
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