# C++ Program to Implement Cohen Sutherland Algorithm

Here is implementation of Cohen Sutherland Algorithm in C++

#include
#include
#include
#include
#include #include
typedef struct coordinate
{
int x,y;
char code[4];
}PT;
void drawwindow();
void drawline (PT p1,PT p2,int cl);
PT setcode(PT p);
int visibility (PT p1,PT p2);
PT resetendpt (PT p1,PT p2);
main()
{
int gd=DETECT, gm,v;
PT p1,p2,ptemp;
initgraph(&gd,&gm,”c:\\tc\\bgi “);
cleardevice();
cout<<"\n\n\t\tENTER END-POINT 1 (x,y): "; cin>>p1.x>>p1.y;
cout<<"\n\n\t\tENTER END-POINT 2 (x,y): "; cin>>p2.x>>p2.y;
cleardevice();
drawwindow();
getch();
drawline(p1,p2,15);
getch();
p1=setcode(p1);
p2=setcode(p2);
v=visibility(p1,p2);
switch(v)
{
case 0: cleardevice();
drawwindow();
drawline(p1,p2,15);
break;
case 1: cleardevice();
drawwindow();
break;
case 2: cleardevice();
p1=resetendpt (p1,p2);
p2=resetendpt(p2,p1);
drawwindow();
drawline(p1,p2,15);
break;
}
getch();
closegraph();
return(0);
}
void drawwindow()
{
setcolor(RED);
line(150,100,450,100);
line(450,100,450,350);
line(450,350,150,350);
line(150,350,150,100);
}
void drawline (PT p1,PT p2,int cl)
{
setcolor(cl);
line(p1.x,p1.y,p2.x,p2.y);
PT setcode(PT p)
{
PT ptemp;
if(p.y<100) ptemp.code[0]='1'; else ptemp.code[0]='0'; if(p.y>350)
ptemp.code[1]=’1′;
else
ptemp.code[1]=’0′;
if (p.x>450)
ptemp.code[2]=’1′;
else
ptemp.code[2]=’0′;
if (p.x<150) ptemp.code[3]='1'; else ptemp.code[3]='0'; ptemp.x=p.x; ptemp.y=p.y; return(ptemp); } int visibility (PT p1,PT p2) { int i,flag=0; for(i=0;i<4;i++) { if((p1.code[i]!='0')||(p2.code[i]!='0')) flag=1; } if(flag==0) return(0); for(i=0;i<4;i++) { if((p1.code[i]==p2.code[i]) &&(p1.code[i]=='1')) flag=0; } if(flag==0) return(1); return(2); } PT resetendpt (PT p1,PT p2) { PT temp; int x,y,i; float m,k; if( p1.code[3]=='1') x=150; if(p1.code[2]=='1') x=450; if((p1.code[3]=='1')||(p1.code[2]=='1')) { m=(float) (p2.y-p1.y)/(p2.x-p1.x); k=(p1.y+(m*(x-p1.x))); temp.y=k; temp.x=x; for(i=0;i<4;i++) temp.code[i]=p1.code[i]; if(temp.y<=350&&temp.y>=100)
return(temp);
}
if(p1.code[0]==’1′)
y=100;
if(p1.code [1]==’1′)
y=350;
if((p1.code[0]==’1′)||(p1.code[1]==’1′))
{
m=(float)(p2.y-p1.y)/(p2.x-p1.x);
k=(float)p1.x+(float)(y-p1.y)/m;
temp.x=k;
temp.y=y;
for(i=0;i<4;i++) temp.code[i]=p1.code[i]; return(temp); } else return(p1); } [/cpp] Output:

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