#include <graphics.h>  
#include <math.h>  
#include <conio.h>  
#include <iostream.h>  
const int NO=3;  
int col=1;  
float a[3][3]={1,0,0,0,1,0,0,0,1};  
int pts[NO][3];  
void changepts(int p[NO][3]);  
void mult(float b[3][3])  
{  
  float c[3][3];  
  for (int i=0;i<3;i++)  
    for (int j=0;j<3;j++)  
    {  
      c[i][j]=0;  
      for (int k=0;k<3;k++)  
        c[i][j]+=b[i][k]*a[k][j];  
    }  
  for (i=0;i<3;i++)  
    for(int j=0;j<3;j++)  
      a[i][j]=c[i][j];  
}  
void trans(int x, int y)  
{  
  float b[3][3]={1,0,x,0,1,y,0,0,1};  
  mult(b);  
  changepts(pts);  
}  
void scale(float sx, float sy)  
{  
  float b[3][3]={sx,0,0,0,sy,0,0,1};  
  mult(b);  
  changepts(pts);  
}  
void rot(float angle)  
{  
  angle*=M_PI/180;  
  float b[3][3]={cos(angle),-sin(angle),0,sin(angle),cos(angle),0,0,0,1};  
  mult(b);  
  changepts(pts);  
}  
void changepts(int p[NO][3])  
{  
  setcolor(col++);  
  for (int i=0;i<NO;i++)  
  {  
      int q[3];  
      q[0]=(p[i][0]*a[0][0]+p[i][1]*a[0][1]+a[0][2]);  
      q[1]=(p[i][0]*a[1][0]+p[i][1]*a[1][1]+a[1][2]);  
      q[2]=1;  
      for (int j=0;j<3;j++)  
        p[i][j]=q[j];  
  }  
  a[0][0]=1;  
  a[0][1]=0;  
  a[0][2]=0;  
  a[1][0]=0;  
  a[1][1]=1;  
  a[1][2]=0;  
  a[2][0]=0;  
  a[2][1]=0;  
  a[2][2]=1;  
}  
void dpoly(int p[NO][3])  
{  
  for (int i=0;i<NO;i++)  
    line(p[i][0]+getmaxx()/2, getmaxy()/2-p[i][1], p[(i+1)%NO][0]+getmaxx()/2,getmaxy()/2-p[(i+1)%NO][1]);  
}  
void main()  
{  
  int gdriver = DETECT, gmode = VGAHI;  
  initgraph(&gdriver, &gmode, "");  
  for (int i=0;i<NO;i++)  
  {  
    cout<<"Enter data for point "<<i+1;  
    cin>>pts[i][0]>>pts[i][1];  
    pts[i][2]=1;  
  }  
  cleardevice();  
  dpoly(pts);  
  int cho;  
  do  
  {  
    cout<<"Enter 1 for translation\n\t2 for scaling\n\t3 for rotation ";  
    cho=getche();  
    cout<<endl;  
    switch(cho)  
    {  
      case '1':  
      {  
        int x1,y1;  
        cout<<"Enter the value of x ";  
        cin>>x1;  
        cout<<"Enter the value of y ";  
        cin>>y1;  
        trans(x1,y1);  
        dpoly(pts);  
        break;  
      }  
      case '2':  
      {  
        float sx,sy;  
        int x1,y1;  
        cout<<"Enter the value of x ";  
        cin>>x1;  
        cout<<"Enter the value of y ";  
        cin>>y1;  
        trans(-x1,-y1);  
        cout<<"Enter the value of x scale";  
        cin>>sx;  
        cout<<<span class='cpp06'>"Enter the value of y scale"</span>;  
        cin>>sy;  
        scale(sx,sy);  
        trans(x1,y1);  
        dpoly(pts);  
        break;  
      }  
      case '3':  
      {  
        int x1,y1;  
        cout<<"Enter the value of x ";  
        cin>>x1;  
        cout<<"Enter the value of y ";  
        cin>>y1;  
        trans(-x1,-y1);  
        float angle;  
        cout<<"Enter the angle in degrees ";  
        cin>>angle;  
        rot(angle);  
        trans(x1,y1);  
        dpoly(pts);  
        break;  
      }  
    }  
  }while (cho!='0');  
  getch();  
}