lineandcircle.cpp

#include <graphics.h>
#include<iostream>
#include <math.h>
using namespace std;
void circlebres(float x1,float y1,float r)
{
float x,y,p;
x=0;
y=r;
p=3-(2*r); // initial decision parameter
while(x<=y)
{
putpixel(x1+x,y1+y,WHITE); /* drawing pixel in each octant*/
putpixel(x1-x,y1+y,WHITE);
putpixel(x1+x,y1-y,WHITE);
putpixel(x1-x,y1-y,WHITE);
putpixel(x1+y,y1+x,WHITE);
putpixel(x1+y,y1-x,WHITE);
putpixel(x1-y,y1+x,WHITE);
putpixel(x1-y,y1-x,WHITE);
x=x+1;
if(p<0)
{
 p=p+4*(x)+6;
}
else
{
 p=p+4*(x-y)+10;
 y=y-1;
}
delay(40);
}
}
void drawline(int x1,int y1,int x2,int y2)
{
 int dx,dy,m,s;
 float xi,yi,x,y;
 dx = x2 - x1;
 dy = y2 - y1;
 if (abs(dx) > abs(dy))
 s = abs(dx);
 else
 s = abs(dy);
 xi = dx / (float) s;
 yi = dy / (float) s;
 x = x1;
 y = y1;
 putpixel(x1, y1, WHITE);
 for (m = 0; m < s; m++)
 {
 putpixel(x, y, WHITE);
 x += xi;
 y += yi;
 
 }
delay(500);
}
int main()
{
 int xc,yc,r;
 cout<<" enter center coordinates : ";
 cin>>xc>>yc;
 cout<<"enter redius : ";
 cin>>r;
 int gd=DETECT,gm=DETECT,x1,y1,x2,y2;
 initgraph(&gd,&gm,NULL);
 
 circlebres(xc,yc,r); //inside circle
 double height,side;
 //side=r/0.577;
 //height=1.73*side;
 
 side=1.73*r;
 height=1.73*side;
 drawline(xc-side,yc+r,xc+side,yc+r); //base line
 delay(300);
 drawline(xc-side,yc+r,xc,yc+r-height);// left line
 drawline(xc,yc+r-height,xc+side,yc+r); // right line
 circlebres(xc,yc,height-r);//outer circle
delay(3000);
 closegraph();
}