DDA Algorithm

Program to implement DDA Line Drawing Algorithm

#include
#include
#include
#include
#include
#include
#include
class lines
{
private:
int length,x1,y1,x2,y2,x,y,dx,dy,wx,wy,w,width;
public:
lines(); //Constructor
void showline();
int sign(int);
};

int lines::sign(int xx)
{
if(xx<0) return -1; if(xx==0) return 0; if(xx>0)
return 1;
return 0;
}
lines::lines()
{
x=0;y=0;
cout<<"Enter The Co-Ordinates (x1,y1) "; cin>>x1>>y1;
cout<<"Enter The Co-Ordinates (x2,y2) "; cin>>x2>>y2;
cout<<"Enter The Width Of The Line "; cin>>width;
}

void lines::showline()
{
char *s,*s1;
if(abs(x2-x1)>=abs(y2-y1))
length=abs(x2-x1);
else
length=abs(y2-y1);
w=width;
wx=((w-1)/2)*(sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1))/abs(y2-y1));
wy=((w-1)/2)*(sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1))/abs(x2-x1));
dx=(x2-x1)/length;
dy=(y2-y1)/length;
if(dy>dx)
wy=wx;
x=x1+0.5*sign(dx);
y=y1+0.5*sign(dy);
int i=1;
setcolor(0);
while(i<=length) { for(int j=0;j=6;i++,j--)
{
xx+=10;
outtextxy(xx,10,mess[i]);
xxx-=10;
outtextxy(xxx,10,mess[j]);
delay(100);
}
for(i=130;i<=510;i+=10)
for(j=50;j<=430;j+=10)
putpixel(i,j,15);
for(i=130;i<=510;i+=10)
{
if(i==320)
continue;
outtextxy(i,237,"+");
}
for(i=50;i<=430;i+=10)
{
if(i==240)
continue;
outtextxy(317,i,"-");
}
outtextxy(310,230,"O");
outtextxy(530,240,"X");
outtextxy(320,450,"-Y");
outtextxy(100,240,"-X");
outtextxy(320,30,"Y");
a.showline();
closegraph();
}