Line Class Malfunction

Hi there. I'm programming this project called 'Canvas', in which I'm practicing and implementing Classes, which is what are giving me on the University. This 'Class Line' is supposed to draw a line, using functions and services from 'Class Point' which is one we made in class. The problem is that, it compiles perfectly but, when plotting the points and drawing the line, it gives me 2 weird results: one is that I enter coordinates for an horizontal line,which the program draws like a vertical line wherever the program wants. The second weird result is that, when I enter the coordinates for a vertical or diagonal line, the line is drawn in little segments, and wherever the program wants. I've been trying to resolve this since 4:30PM of today, and I haven't got to the solution. Any help?

Here are the 2 Clases, Line and Point, and my 'Driver'(main), and also a link to a Print Screen of the results that I'm getting.

http://img22.imageshack.us/img22/1240/prtscp.png

#pragma once
#include "Point.h"
class Line
{
private:
	Point initial;
	Point final;
	char symbol;
	double x1,y1,x2,y2;
public:
	Line(double x1=0.0,double y1=0.0,double x2=4.0,double y2=4.0,char symbol='+');
	Line(const Point & initial,const Point & final);
	Line(const Line & oneLine);
	~Line();
	Line & operator =(const Line & oneLine);
	const Point & getInitialPoint()const;
	const Point & getFinalPoint()const;
	void changeInitialPoint(const Point & initial);
	void changeFinalPoint(const Point & final);
	double Long()const;
	void askExtremes();
	bool isHorizontal()const;
	bool isVertical()const;
	bool isDiagonal()const;
	bool hasSlope()const;
	friend ostream & operator<<(ostream & out,Line & oneLine);
	bool Include(double x,double y)const;
	void Show()const;
	double M()const;
	double B()const;
	bool inRangeHorizontal(double x,double y)const;
	bool inRangeVertical(double x,double y)const;
	bool inRangeDiagonal(double x,double y)const;
	bool inRangeX(double x)const;
	bool inRangeY(double y)const;
};

#include "Line.h"

Line::Line(double x1, double y1, double x2, double y2, char symbol):initial(x1,y1),final(x2,y2)
{}
Line::Line(const Point &initial, const Point &final):initial(initial),final(final)
{}
Line::Line(const Line &oneLine):initial(oneLine.initial),final(oneLine.final)
{
	this->symbol=symbol;
}
Line::~Line()
{}
Line & Line::operator =(const Line &oneLine)
{
	(this->initial)=(oneLine.initial);
	(this->final)=(oneLine.final);
	(this->symbol)=(oneLine.symbol);
	return(*this);
}
const Point & Line::getInitialPoint() const
{
	return(this->initial);
}
const Point & Line::getFinalPoint() const
{
	return(this->final);
}
void Line::changeInitialPoint(const Point &initial)
{
	(this->initial).changeX(initial.getX());
	(this->initial).changeY(initial.getY());
}
void Line::changeFinalPoint(const Point &final)
{
	(this->final).changeX(final.getX());
	(this->final).changeY(final.getY());
}
double Line::Long() const
{
	return((this->initial).distance(this->final));
}
bool Line::isHorizontal() const
{
	return((this->initial).getY()==(this->final).getY());
}
bool Line::isVertical() const
{
	return((this->initial).getX()==(this->final).getX());
}
bool Line::isDiagonal() const
{
	return(!(this->isVertical()||this->isHorizontal()));
}
bool Line::hasSlope() const
{
	return(!(this->isVertical()));
}
void Line::askExtremes()
{
	cout<<"Enter the initial point: "<<endl;
	(this->initial).askCoordinates();
	cout<<"Enter the final point: "<<endl;
	(this->final).askCoordinates();
}
ostream & operator<<(ostream & out,Line & oneLine)
{
	out<<"Initial Point: ";
	out<<(oneLine.initial);
	out<<endl<<"Final Point: ";
	out<<(oneLine.final);
	if(oneLine.isHorizontal())
	{
		out<<endl<<"The line is horizontal";
	}
	else
	{
		if(oneLine.isVertical())
		{
			out<<endl<<"The line is vartical";
		}
	}
	if(oneLine.hasSlope())
	{
		out<<endl<<"The line has slope";
	}
	else
	{
		out<<endl<<"The line has indefinite slope";
	}
	return(out);
}
bool Line::Include(double x,double y)const
{
	bool Is;
	if(this->isHorizontal())
	{
		Is=this->inRangeHorizontal(x,y);
	}
	else
	{
		if(this->isVertical())
		{
			Is=this->inRangeVertical(x,y);
		}
		else
		{
			if(this->isDiagonal())
			{
				Is=this->inRangeDiagonal(x,y);
			}
			else
			{
				Is=false;
			}
		}
	}
	return(Is);
}
void Line::Show() const
{
	cout<<this->symbol<<endl;
}
double Line::M()const
{
	double dx,dy;

	dy=this->final.getY()-this->initial.getY();
	dx=this->final.getX()-this->initial.getX();

	return (dy/dx);
}

double Line::B()const
{
	return(this->final.getY()-(this->M()*this->final.getX()));
}
bool Line::inRangeHorizontal(double x,double y)const
{
	return((this->initial.getY()==y)&&(((this->initial.getX()<=x)&&this->final.getX()>=x)||(this->final.getX()<=x&&this->initial.getX()>=x)));
}
bool Line::inRangeVertical(double x,double y)const
{
	return((this->initial.getX()==x)&&(((this->initial.getY()<=y)&&this->final.getY()>=y)||(this->final.getY()<=y&&this->initial.getY()>=y)));
}
bool Line::inRangeDiagonal(double x,double y)const
{
	return((this->inRangeX(x)&&this->inRangeY(y))&&(y==(this->M()*x+this->B())));
}
bool Line::inRangeX(double x) const
{
	return((this->initial.getX()<=x&&this->final.getX()>=x)||(this->final.getX()<=x&&this->initial.getX()>=x));
}
bool Line::inRangeY(double y) const
{
	return((this->initial.getY()<=y&&this->final.getY()>=y)||(this->final.getY()<=y&&this->initial.getY()>=y));
}

#pragma once
#include <iostream>
#include <cstring>
#include <cmath>
using namespace std;
class Point
{
private :
	double x;
	double y;
	char symbol;
	bool Is;
public:
	Point(double x=0.0,double y=0.0,char symbol='*');
	Point(const Point & onePoint);
    ~Point();
	Point & operator =(const Point & onePoint);
	double getX()const ; 
	double getY()const;
	void changeX(double x);
	void changeY(double y);
	double distance(const Point & onePoint)const;
	void askCoordinates();
	friend ostream & operator<<(ostream & output,Point & onePoint);
	bool include(double x,double y)const;
	void show()const;
};

#include "Point.h"
#include <iostream>
#include <cstring>
#include <cmath>

Point::Point(double x, double y,char symbol)
{
	this->x=x;
	this->y=y;
	this->symbol=symbol;
}
Point::Point(const Point & onePoint)
{
	this->x=onePoint.x;
	this->y=onePoint.y;
	this->symbol=onePoint.symbol;
}
Point::~Point()
{
}
Point & Point::operator =(const Point & onePoint)
{
	this->x=onePoint.x;
	this->y=onePoint.y;
	this->symbol=onePoint.symbol;
	return(*this);
}
double Point::getX() const
{
	return(this->x);
}
double Point::getY() const
{
	return(this->y);
}
void Point::changeX(double x)
{
	this->x=x;
}
void Point::changeY(double y)
{
	this->y=y;
}
double Point::distance(const Point & onePoint) const
{
	return(sqrt((pow(this->x-onePoint.x,2))+(pow(this->y-onePoint.y,2))));
}
void Point::askCoordinates()
{
	cout<<"Enter the new 'X' coordinate: ";
	cin>>this->x;
	cout<<"Enter the new 'Y' coordinate: ";
	cin>>this->y;
}
ostream & operator<<(ostream & output,Point & onePoint)
{
	output<<"("<<onePoint.x<<","<<onePoint.y<<")";
	return(output);
}
bool Point::include(double x, double y) const
{
	return((this->x==x)&&(this->y==y));
}
void Point::show() const
{
	cout<<this->symbol<<endl;
}

#include "Line.h"
#include "Point.h"
#include <iostream>
using namespace std;

int main()
{
	Point p1;
	Point p2;
	Point p3;
	Line l1;
	Line l2;
	//Line l3;

	//p1.askCoordinates();
	//p2.askCoordinates();
	//p3.askCoordinates();
	l1.askExtremes();
	l2.askExtremes();

	for(int y=0;y<=40;y++)
	{
		for(int x=0;x<=40;x++)
		{
			if(p1.include(x,y))
			{
				p1.show();
			}
			else
			{
				if(p2.include(x,y))
				{
					p2.show();
				}
				else
				{
					if(p3.include(x,y))
					{
						p3.show();
					}
					else
					{
						if(l1.Include(x,y))
						{
							l1.Show();
						}
						else
						{
							if(l2.Include(x,y))
							{
								l2.Show();
							}
							else
							{
								cout<<" ";
							}
						}
					}
				}
			}
		}
		cout<<endl;
	}
}

Alkaselzer (8)

I've got to the conclusion that there's is something in the return of Line::inRangeVertical, but I have no clue of what I'm supposed to change, to repair...

jsmith (5804)

You can't compare floating point numbers for equality like you are doing in many places.

The best you can do is compare for equality within some epsilon.

As a side note, your code is very hard to read for two reasons.

First, no spaces.

Second, repeated use of this-> for everything.

Alkaselzer (8)

I'm sorry, my english is not the best, and my c++ vocabulary isn't very small... what is an epsilon?

Zhuge (4664)

Epslilion meaning a really small value; the idea is that floating point numbers are not stored to perfect accuracy in memory, so you will have to compare two floats to see if they are within 0.001 or whatever value you consider the best for your application.

Did a quick Google search:
http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm

Alkaselzer (8)

thanx! I'll give it a try and let you know!

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