Rectangle class with three constructors - c++

Question

I need to complete the Rectangle class. Write 3 constructors and a destructor to satisfy the main() below. Use constructor initializers for each constructor.
This is what is done:
class Rectangle
{
float* length;
float* width;
...
???
...
};
int main()
{
Rectangle r1;
Rectangle r2(4.5,2.3);
Rectangle r3(r2);
}
This is how I filled up the rectangle class:
class rectangle
{
private:
float* length;
float* width;
public:
rectangle(); //default constructor
rectangle(double w, double l); //constructor with parameters
rectangle(const rectangle&); //copy constructor
~rectangle(void);
double getWidth(void);
double getLength(void);
double perimeter(void) const;
double area(void) const;
};
...........
...........
...........
int main()
{
rectangle r1;
rectangle r2(4.5,2.3);
rectangle r3(r2);
//statements
}
I just want to know if am doing it right or wrong. Can anyone see if am missing smth or need to add to rectanglr class?!

Answer 1

I think that you are doing wrong because the definition
Rectangle r2(4.5,2.3);
does not have a corresponding constructor. Also take into account that the class in the assignment is named as Rectangle not rectangle.:)
I think that instead of length and width (why did you declare them as pointers?!) you should define four data members that will denote four points of the rectangle.

Answer 2

The declaration and the uses of the three constructors (default constructor, a custom constructor, and a copy constructor) look reasonable. Storing pointers to float does not look reasonable, however: you should just store floats (I would actually store doubles unless I have a reason to assume that there are a huge mount of rectangles). When storing floats, there is actually no need to have a copy constructor or a destructor. If you insist in storing float* and, thus, allocate memory, you shall also implement a copy assignment:
rectangle& rectangle::operator= (rectangle other) {
other.swap(*this);
return *this;
}
void rectangle::swap(rectangle& other) {
std::swap(this->length, other.length);
std::swap(this->width, other.width);
}