(Rectangle Class) Create a class Rectangle with attributes length and width, each of which defaults to 1. Provide member functions that calculate the perimeter and the area of the rectangle. Also, provide set and get functions for the length and width attributes. The set functions should ver- ify that length and width are each floating-point numbers larger than 0.0 and less than 20.0.

Question

What will be an ideal response?

Answer 1

```
#ifndef RECTANGLE_H
#define RECTANGLE_H

class Rectangle
{
public:
Rectangle( double = 1.0, double = 1.0 ); // default constructor
void setWidth( double w ); // set width
void setLength( double l ); // set length
double getWidth(); // get width
double getLength(); // get length
double perimeter(); // perimeter
double area(); // area
private:
double length; // 1.0 < length < 20.0
double width; // 1.0 < width < 20.0
}; // end class Rectangle

#endif
```
```
// Member-function definitions for class Rectangle.
#include "Rectangle.h" // include definition of class Rectangle

Rectangle::Rectangle( double w, double l )
{
setWidth(w); // invokes function setWidth
setLength(l); // invokes function setLength
} // end Rectangle constructor

void Rectangle::setWidth( double w )
{
width = w > 0 && w < 20.0 ? w : 1.0; // sets width
} // end function setWidth

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

double Rectangle::getWidth()
{
return width;
} // end function getWidth

double Rectangle::getLength()
{
return length;
} // end function getLength

double Rectangle::perimeter()
{
return 2 * ( width + length ); // returns perimeter
} // end function perimeter

double Rectangle::area()
{
return width * length; // returns area
} // end function area
```
```
#include
#include
#include "Rectangle.h" // include definition of class Rectangle
using namespace std;

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

cout << fixed;
cout << setprecision( 1 );

// output Rectangle a
cout << "a: length = " << a.getLength() << "; width = "
<< a.getWidth() << "; perimeter = " << a.perimeter()
<< "; area = " << a.area() << '\n';

// output Rectangle b
cout << "b: length = " << b.getLength() << "; width = "
<< b.getWidth() << "; perimeter = " << b.perimeter()
<< "; area = " << b.area() << '\n';

// output Rectangle c; bad values attempted
cout << "c: length = " << c.getLength() << "; width = "
<< c.getWidth() << "; perimeter = " << c.perimeter()
<< "; area = " << c.area() << endl;
} // end main
```
a: length = 1.0; width = 1.0; perimeter = 4.0; area = 1.0
b: length = 5.0; width = 4.0; perimeter = 18.0; area = 20.0
c: length = 1.0; width = 1.0; perimeter = 4.0; area = 1.0