1.  
2. #include<stdio.h>
3. #include<conio.h>
4. #include<graphics.h>
5. #include<math.h>
6. void clip(float,float,float);
7. int i,j=0,n;
8. int rx1,rx2,ry1,ry2;
9. float x1[8],y1[8];
10. int main()
11. {
12. int gd=DETECT,gm;
13. int i,n;
14. float x[8],y[8],m;
15. //clrscr();
16. initgraph(&gd,&gm,"");
17. printf("coordinates for rectangle : ");
18. scanf("%d%d%d%d",&rx1,&ry1,&rx2,&ry2);
19. printf("no. of sides for polygon : ");
20. scanf("%d",&n);
21. printf("coordinates : ");
22. for(i=0;i<n;i++)
23. {
24. scanf("%f%f",&x[i],&y[i]);
25. }
26. cleardevice();
27. outtextxy(10,10,"Before clipping");
28. outtextxy(10,470,"Press any key....");
29. rectangle(rx1,ry1,rx2,ry2);
30. for(i=0;i<n-1;i++)
31. line(x[i],y[i],x[i+1],y[i+1]);
32. line(x[i],y[i],x[0],y[0]);
33. getch();
34. cleardevice();
35. for(i=0;i<n-1;i++)
36. {
37. m=(y[i+1]-y[i])/(x[i+1]-x[i]);
38. clip(x[i],y[i],m);
39. clip(x[i+1],y[i+1],m);
40. }
41. m=(y[i]-y[0])/(x[i]-x[0]);
42. clip(x[i],y[i],m);
43. clip(x[0],y[0],m);
44. outtextxy(10,10,"After clipping");
45. outtextxy(10,470,"Press any key....");
46. rectangle(rx1,ry1,rx2,ry2);
47. for(i=0;i<j-1;i++)
48. line(x1[i],y1[i],x1[i+1],y1[i+1]);
49. getch();
50. }
51.  
52. void clip(float e,float f,float m)
53. {
54. while(e<rx1,e>rx2,f<ry1,f>ry2)
55. {
56. if(e<rx1)
57. {
58. f+=m*(rx1-e);
59. e=rx1;
60. }
61. else if(e>rx2)
62. {
63. f+=m*(rx2-e);
64. e=rx2;
65. }
66. if(f<ry1)
67. {
68. e+=(ry1-f)/m;
69. f=ry1;
70. }
71. else if(f>ry2)
72. {
73. e+=(ry2-f)/m;
74. f=ry2;
75. }
76. }
77. x1[j]=e;
78. y1[j]=f;
79. j++;
80. }
81.