#include<iostream.h>
#include<conio.h>
#include<graphics.h>
#include<dos.h>
#include<math.h>
//rotate a polygon
void main()
{
clrscr();
int gd=DETECT,gm,x1,y1,x2,y2,x3,y3,x4,y4,x5,y5,x6,y6;
initgraph(&gd,&gm,"c:\\tc\\bgi");
setcolor(10);
cout<<"Enter x1 & y1 value: ";
cin>>x1>>y1;
cout<<"Enter x2 & y2 value: ";
cin>>x2>>y2;
cout<<"Enter x3 & y3 value: ";
cin>>x3>>y3;

line(x1,y1,x2,y2);
line(x2,y2,x3,y3);
line(x3,y3,x1,y1);
x4=x1*cos(45)+y1*sin(45);
y4=x1*sin(45)-y1*cos(45);
x5=x2*cos(45)+y2*sin(45);
y5=x2*sin(45)-y2*cos(45);
x6=x3*cos(45)+y3*sin(45);
y6=x3*sin(45)-y3*cos(45);
line(x4,y4,x5,y5);
line(x5,y5,x6,y6);
line(x6,y6,x4,y4);
getch();
}