In Class - class
Excercise 6-12
  1. What is the class called.?
    Rectangle______________

  2. What data members are in the class?
    length and width both doubles

  3. What access modifier should the data member have?
    private______________

  4. What member functions need to be defined?
    _area_______________
    _perimeter__________
    _setLength__________
    _setWidth___________
    _getWidth___________
    _getLength___________

  5. What does the prototype look like for the area member function?
    _double area(void);________

  6. What does a get for length prototype look like?
    _double getLength(void);___

  7. What does a set for length prototype look like?
    _ void setLength(double l);

  8. Write the function for area. 
    double Rectangle::area(void) 
{
	return length * width;
}


  9. How would the area function be invoked? 
       Double a;

   cout << "a : area      =" << a.area()      << endl << endl;

  10. Do we need multiple (overloaded) functions for the contruction?
    It should be able to handle the following instances.

    Rectangle a;

    Rectangle b(20.0); // Set the length

    Rectanglec(10.0,10.0) // set the length and widt
    No we can handle this with deafult arguments:

  11. Write the constructor 

    Rectangle(double=1.0, double=1.0);  // Constructor

Rectangle::Rectangle(double w, double l)
{
	setWidth(w);
	setLength(l);
}

    .

  12. What does the header file look like for this project?? 
    //  
#ifndef crect
#define crect

class Rectangle {

public:
	Rectangle(double=1.0, double=1.0);  // Constructor
	double perimeter(void);
	double area(void);
	void   setWidth(double w);
	void   setLength(double l);
	double getWidth(void);
	double getLength(void);

private:
	double length;
	double width;
};

#endif

  13. Write the member functions 
    //
//  Member Functions for Rectangle
//
#include 
#include "crect.h"


//   Constructor
Rectangle::Rectangle(double w, double l)
{
	setWidth(w);
	setLength(l);
}

double Rectangle::area(void) 
{
	return length * width;
}

double Rectangle::perimeter(void)
{
	return 2*(length+width);
}

void Rectangle::setWidth(double w)
{
	if ( w> 0 && w < 20.0)
		width=w;
	else
		width=1.0;
}

void Rectangle::setLength(double l)
{
	length= l > 0 && l < 20.0 ? l : 1.0;
}

double Rectangle::getWidth(void)
{
	return width;
}

double Rectangle::getLength(void)
{
	return length;
}


  14. Write the main file. 

    // 
// Driver
//
#include <iostream.h>
#include <iomanip.h>
#include "crect.h"

void main()
{
	Rectangle a;
	Rectangle b(4.0,5.0);
	Rectangle c(67.0,888.0);

	cout << setiosflags(ios::fixed | ios::showpoint);
	cout << setprecision(1);

	
	//  Rectangle a
	cout << "a : length    =" << a.getLength() << endl;
	cout << "a : width     =" << a.getWidth()  << endl;
	cout << "a : perimeter =" << a.perimeter() << endl;
	cout << "a : area      =" << a.area()      << endl << endl;

	//  Rectangle b
	cout << "b : length    =" << b.getLength() << endl;
	cout << "b : width     =" << b.getWidth()  << endl;
	cout << "b : perimeter =" << b.perimeter() << endl;
	cout << "b : area      =" << b.area()      << endl << endl;

	//  Rectangle c
	cout << "c : length    =" << c.getLength() << endl;
	cout << "c : width     =" << c.getWidth()  << endl;
	cout << "c : perimeter =" << c.perimeter() << endl;
	cout << "c : area      =" << c.area()      << endl << endl;

}


  15. Compile the project and run it! 
    --------------------Configuration: crect - Win32 Debug--------------------
Compiling...
crect.cpp
crectc.cpp
Linking...

crect.exe - 0 error(s), 0 warning(s)

a : length    =1.0
a : width     =1.0
a : perimeter =4.0
a : area      =1.0

b : length    =5.0
b : width     =4.0
b : perimeter =18.0
b : area      =20.0

c : length    =1.0
c : width     =1.0
c : perimeter =4.0
c : area      =1.0

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