#include"stdio.h"
#include"conio.h"
#include"graphics.h"
void main()
{
int gd=DETECT, gm;
float i,xmax,ymax,xmin,ymin,x1,y1,x2,y2,m;
float start[4],end[4],code[4];
clrscr();
initgraph(&gd,&gm,"");
printf("\n\tPlease enter the bottom left co-ordinate of viewport: ");
scanf("%f %f",&xmin,&ymin);
printf("\n\tPlease enter the top right co-ordinate of viewport: ");
scanf("%f %f",&xmax,&ymax);
printf("\nPlease enter the co-ordinates for starting point of line: ");
scanf("%f %f",&x1,&y1);
printf("\nPlease enter the co-ordinates for ending point of line: ");
scanf("%f %f",&x2,&y2);
for(i=0;i
{
start[i]=0;
end[i]=0;
}
m=(y2-y1)/(x2-x1);
if(x1 if(x1 >xmax) start[1]=1;
if(y1 >ymax) start[2]=1;
if(y1 if(x2 if(x2 >xmax) end[1]=1;
if(y2 >ymax) end[2]=1;
if(y2 for(i=0;i

code[i]=start[i]&&end[i];

if((code[0]==0)&&(code[1]==0)&&(code[2]==0)&&(code[3]==0))
{
if((start[0]==0)&&(start[1]==0)&&(start[2]==0)&&(start[3]==0)&&(end[0]==0)&&(end[1]==0)&&(end[2]==0)&&(end[3]==0))
{
cleardevice();
    printf("\n\t\tThe line is totally visible\n\t\tand not a clipping candidate");
    rectangle(xmin,ymin,xmax,ymax);
    line(x1,y1,x2,y2);
    getch();
}
else
{
    cleardevice();
    printf("\n\t\tLine is partially visible");
    rectangle(xmin,ymin,xmax,ymax);
    line(x1,y1,x2,y2);
    getch();

if((start[2]==0)&&(start[3]==1))
{
     x1=x1+(ymin-y1)/m;
     y1=ymin;
}
if((end[2]==0)&&(end[3]==1))
{
     x2=x2+(ymin-y2)/m;
     y2=ymin;
}
if((start[2]==1)&&(start[3]==0))
{
     x1=x1+(ymax-y1)/m;
     y1=ymax;
}
if((end[2]==1)&&(end[3]==0))
{
     x2=x2+(ymax-y2)/m;
     y2=ymax;
}
if((start[1]==0)&&(start[0]==1))
{
     y1=y1+m*(xmin-x1);
     x1=xmin;
}
if((end[1]==0)&&(end[0]==1))
{
     y2=y2+m*(xmin-x2);
     x2=xmin;
}
if((start[1]==1)&&(start[0]==0))
{
     y1=y1+m*(xmax-x1);
     x1=xmax;
}
if((end[1]==1)&&(end[0]==0))
{
     y2=y2+m*(xmax-x2);
     x2=xmax;
}

clrscr();
cleardevice();
printf("\n\t\tAfter clippling:");
rectangle(xmin,ymin,xmax,ymax);
line(x1,y1,x2,y2);
getch();
}
}
else
{
    clrscr();
    cleardevice();
    printf("\nLine is invisible");
    rectangle(xmin,ymin,xmax,ymax);
}
getch();
closegraph();
}

Input:

Output: