assignment no: 8
// program for polygon

#include<iostream>
#include<graphics.h>
using namespace std;

class dline
{
    protected: int x1,y1,x2,y2;
    public:
    dline()
    {
        x1=0,y1=0,x2=0,y2=0;
    }
    void step1()
    {
        cout<<"\n Enter x1: ";cin>>x1;
        cout<<"\n Enter y1: ";cin>>y1;
    }
    void step2()
    {
        cout<<"\n Enter x2: ";cin>>x2;
        cout<<"\n Enter y2: ";cin>>y2;
    }
    void drawl()
    {
        float x,y,dx,dy,len;
        int i;
          
        dx=abs(x2-x1);
        dy=abs(y2-y1);
      
        if(dx >= dy)
        {

            len=dx;
        }
        else
        {
            len=dy;
        }

        dx=(x2-x1)/len;
        dy=(y2-y1)/len;

        x = x1 + 0.5;
        y = y1 + 0.5;      

        i=1;

        while(i<=len)
        {
            putpixel(x,y,15);
            x = x + dx;
            y = y + dy;
            i = i + 1;      
        }

        putpixel(x,y,15);

    }
};

class rect: public dline  //Rectangle
{
    private: int w,l;
    public:
    void setrect()
    {
        dline::step1();
        cout<<"\n Enter width: ";cin>>w;
        cout<<"\n Enter length: ";cin>>l;
    }  
    void drawrect()
    {
        x2=x1;
        y2=y1+w;  
        dline::drawl();  //left

        x2=x1+l;
        y2=y1;  
        dline::drawl();  //top

        x1=x1;
        y1=y1+w;      
        x2=x1+l;
        y2=y1;  
        dline::drawl();  //bottom

        x1=x1+l;
        y1=y1-w;      
        x2=x1;
        y2=y1+w;      
        dline::drawl();  //right
    }
};  

class square: public dline  //Square
{
    private: int l;
    public:
    void setsquare()
    {
        dline::step1();
        cout<<"\n Enter length: ";cin>>l;
    }  
    void drawsquare()
    {
        x2=x1;
        y2=y1+l;  
        dline::drawl();  //left

        x2=x1+l;
        y2=y1;  
        dline::drawl();  //top

        x1=x1;
        y1=y1+l;      
        x2=x1+l;
        y2=y1;  
        dline::drawl();  //bottom

        x1=x1+l;
        y1=y1-l;      
        x2=x1;
        y2=y1+l;      
        dline::drawl();  //right
    }
};  
  
class triangle: public dline  //Triangle
{
    private: int x3,y3;
    public:
    void settri()
    {
        dline::step1();
        dline::step2();
        cout<<"\n Enter x3: ";cin>>x3;
        cout<<"\n Enter y3: ";cin>>y3;
    }  
    void drawtri()
    {
        int tempx,tempy;
        dline::drawl();

        tempx=x2;
        x2=y2;
        x2=x3;
        y2=y3;
        dline::drawl();

        x1=tempx;
        y1=tempy;
        dline::drawl();
    }
};  

int main()
{
  
    int gd=DETECT,gm=VGAMAX;
    int i, x, y, r,ch, xmax,ymax,xmid,ymid;
    char a;
    initgraph(&gd,&gm,NULL);
      
    rect r1;
    square s;
    triangle t;
    do
    {       
     cout<<"\nChoose polygon to draw";
     cout<<"\n1.Rectangle..";
     cout<<"\n2.Square..";
     cout<<"\n3.Triangle..";
     cout<<"\n4.EXIT..";
     cout<<"\nEnter your choice: ";
    cin>>ch;
switch(ch)
{
case 1:
    {  
    r1.setrect();
    r1.drawrect();
    break;
    }
case 2:
        {  
    s.setsquare();
    s.drawsquare();
    break;
    }

case 3:
    {  
    t.settri();
    t.drawtri();
    delay(3000);
    break;
    }
case 4:
        exit;
    break;
}
cout<<"\nDO U Want To Continue y OR n: ";
cin>>a;
}while(a!='n');  
    delay(3000);
    getch();
    closegraph();
    return 0;
}