#include<stdio.h>
#include<conio.h>
#include<graphics.h>
#include<math.h>
main()
{
 int gd=DETECT;
 int gm=DETECT;
 int p,i,j,k,l,m,n,w[4],a[20],b[20],c[20],d[20],x[20],y[20];
 char ch;
 float s,t;
 detectgraph(&gm,&gd);
 initgraph(&gm,&gd,"c:\\turboc\\bgi");
 clrscr();
 cleardevice();
 printf("\nEnter the points of window: ");
 printf("\nLEFT X, LEFT TOP, RIGHT X, RIGHT BOTTOM ");
 scanf("%d%d%d%d",&w[0],&w[1],&w[2],&w[3]);
 printf("\nEnter the number of sides of polygon: ");
 scanf("%d",&n);
 printf("\nEnter the points: ");
 for(i=0;i<n;i++)
 {
  printf("\nEnter the x-y co-ordianates of point %d",i+1);
  scanf("%d%d",&x[i],&y[i]);
 }
 rectangle(w[0],w[1],w[2],w[3]);
 for(i=0;i<n;i++)
 {
  p=i+1;
  if(p==n)
   p=0;
  line(x[i],y[i],x[p],y[p]);
 }
 printf("\nPress any key...");
 getch();
 clrscr();
 cleardevice();
 i=0;
 j=0;
 p=0;
 do
 {
  p=i+1;
  if(p==n)
   p=0;
  if((x[i]==x[p])&&(x[i]<w[0]))
   goto p;
  if((x[i]==x[p])&&(x[i]>w[2]))
   goto p;
  if((y[i]==y[p])&&(y[i]<w[1]))
   goto p;
  if((y[i]==y[p])&&(y[i]>w[3]))
   goto p;
  if(x[i]<=w[0]&&x[p]<=w[0])
   goto p;
  if(y[i]<=w[1]&&y[p]<=w[1])
   goto p;
  if(x[i]>=w[2]&&x[p]>=w[2])
   goto p;
  if(y[i]>=w[3]&&y[p]>=w[3])
   goto p;
  s=(y[p]-y[i]+1);
  s=s/(x[p]-x[i]+1);
  if(x[i]<w[0]&&y[i]<w[1]&&s>1)
  {
   t=s*(w[0]-x[i])+y[i];
   a[j]=w[0];
   b[j]=t;
  }
  if(x[i]<w[0]&&y[i]<w[1]&&s<1)
  {
   t=(1/s)*(w[1]-y[i])+x[i];
   a[j]=t;
   b[j]=w[1];
  }
  if(x[i]>w[2]&&y[i]<w[1]&&s<1)
  {
   t=s*(w[2]-x[i])+y[i];
   a[j]=w[2];
   b[j]=t;
  }
  if(x[i]<w[0])
  {
   t=s*(w[0]-x[i])+x[i];
   a[j]=w[0];
   b[j]=t;
  }
  if(y[i]<w[1])
  {
   t=(1/s)*(w[1]-y[i])+x[i];
   a[j]=t;
   b[j]=w[1];
  }
  if(x[i]>w[2])
  {
   t=s*(w[2]-x[i])+y[i];
   a[j]=w[2];
   b[j]=t;
  }
  if(y[i]>w[3])
  {
   t=(1/s)*(w[3]-y[i])+x[i];
   a[j]=t;
   b[j]=w[3];
  }
  if(x[i]>w[0]&&x[i]<w[2]&&y[i]>w[1]&&y[i]<w[3])
  {
   a[j]=x[i];
   b[j]=y[i];
  }
  if(x[p]<w[0]&&y[p]<w[1]&&s>1)
  {
   t=s*(w[0]-x[p])+y[p];
   c[j]=w[0];
   d[j]=t;
  }
  if(x[p]<w[0]&&y[p]<w[1]&&s<1)
  {
   t=(1/s)*(w[1]-y[p])+x[p];
   c[j]=t;
   d[j]=w[1];
  }
  if(x[p]>w[2]&&y[p]<w[1]&&s<1)
  {
   t=s*(w[2]-x[p])+y[p];
   a[j]=w[2];
   b[j]=t;
  }
  if(x[p]<w[0])
  {
   t=s*(w[0]-x[p])+y[p];
   c[j]=w[0];
   d[j]=t;
  }
  if(x[p]>w[2])
  {
   t=s*(w[2]-x[p])+y[p];
   c[j]=w[2];
   d[j]=t;
  }
  if(y[p]<w[1])
  {
   t=(1/s)*(w[1]-y[p])+x[p];
   c[j]=t;
   d[j]=w[1];
  }
  if(y[p]>w[3])
  {
   t=(1/s)*(w[3]-y[p])+x[p];
   c[j]=t;
   d[j]=w[3];
  }
  if(x[p]>w[0]&&x[p]<w[2]&&y[p]>w[1]&&y[p]<w[3])
  {
   c[j]=x[p];
   d[j]=y[p];
  }
  j++;
 p: i++;
  }while(i<n);
  rectangle(w[0],w[1],w[2],w[3]);
  for(i=0;i<j;i++)
  {
   line(a[i],b[i],c[i],d[i]);
  }
  getch();
 }