# Program to fill a Circle using Scan-Line Circle Fill Algorithm using Polar Coordinates

``` # include <iostream.h>
# include <graphics.h>
# include    <conio.h>
# include     <math.h>

void show_screen( );

void Fill_circle(const int,const int,const int);

void Circle(const int,const int,const int);
void Line(const int,const int,const int,const int);

int main( )
{
int driver=VGA;
int mode=VGAHI;

int x=0;
int y=0;
int r=0;

do
{
show_screen( );

gotoxy(8,10);
cout<<\"Coordinates of Center Point (x,y) :\";

gotoxy(8,11);
cout<<\"ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ\";

gotoxy(12,13);
cout<<\"Enter the value of x = \";
cin>>x;

gotoxy(12,14);
cout<<\"Enter the value of y = \";
cin>>y;

gotoxy(8,18);
cout<<\"Radius of Circle : r :\";

gotoxy(8,19);
cout<<\"ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ\";

gotoxy(12,21);
cout<<\"Enter the value of r = \";
cin>>r;

initgraph(&driver,&mode,\"..\\\\Bgi\");

setcolor(15);
Circle(x,y,r);

setcolor(9);
Fill_circle(x,y,(r-1));

setcolor(15);
outtextxy(110,460,\"Press <Enter> to continue or any other key to exit.\");

int key=int(getch( ));

if(key!=13)
break;
}
while(1);

return 0;
}

//---------------------------  Fill_circle( )  --------------------------//

void Fill_circle(const int x,const int y,const int r)
{
int iterations=(int)((2*r*M_PI)+0.5);
double angle;
int x1;
int y1;

for(int count=0;count<=iterations;count++)
{
angle=(((2*M_PI*count)/iterations)+0.5);
x1=int(x+(r*cos(angle))+0.5);
y1=int(y+(r*sin(angle))+0.5);

Line(x,y,x1,y1);
}
}

//----------------------------  Circle( )  ------------------------------//

void Circle(const int h,const int k,const int r)
{
int color=getcolor( );

int x=0;
int y=r;
int p=(1-r);

do
{
putpixel((h+x),(k+y),color);
putpixel((h+y),(k+x),color);
putpixel((h+y),(k-x),color);
putpixel((h+x),(k-y),color);
putpixel((h-x),(k-y),color);
putpixel((h-y),(k-x),color);
putpixel((h-y),(k+x),color);
putpixel((h-x),(k+y),color);

x++;

if(p<0)
p+=((2*x)+1);

else
{
y--;
p+=((2*(x-y))+1);
}
}
while(x<=y);
}

//------------------------------  Line( )  ------------------------------//

void Line(const int x_1,const int y_1,const int x_2,const int y_2)
{
int color=getcolor( );

int x1=x_1;
int y1=y_1;

int x2=x_2;
int y2=y_2;

if(x_1>x_2)
{
x1=x_2;
y1=y_2;

x2=x_1;
y2=y_1;
}

int dx=abs(x2-x1);
int dy=abs(y2-y1);
int inc_dec=((y2>=y1)?1:-1);

if(dx>dy)
{
int two_dy=(2*dy);
int two_dy_dx=(2*(dy-dx));
int p=((2*dy)-dx);

int x=x1;
int y=y1;

putpixel(x,y,color);

while(x<x2)
{
x++;

if(p<0)
p+=two_dy;

else
{
y+=inc_dec;
p+=two_dy_dx;
}

putpixel(x,y,color);
}
}

else
{
int two_dx=(2*dx);
int two_dx_dy=(2*(dx-dy));
int p=((2*dx)-dy);

int x=x1;
int y=y1;

putpixel(x,y,color);

while(y!=y2)
{
y+=inc_dec;

if(p<0)
p+=two_dx;

else
{
x++;
p+=two_dx_dy;
}

putpixel(x,y,color);
}
}
}

//--------------------------  show_screen( )  ---------------------------//

void show_screen( )
{
restorecrtmode( );
textmode(C4350);

cprintf(\"\\n********************************************************************************\");
cprintf(\"*********************-                                   -**********************\");
cprintf(\"*--------------------- \");

textbackground(1);
cprintf(\" Scan-Line Circle Fill Algorithm \");
textbackground(8);

cprintf(\" ----------------------*\");
cprintf(\"*********************-                                   -**********************\");
cprintf(\"*-****************************************************************************-*\");

for(int count=0;count<42;count++)
cprintf(\"*-*                                                                          *-*\");

gotoxy(1,46);
cprintf(\"*-****************************************************************************-*\");
cprintf(\"*------------------------------------------------------------------------------*\");
cprintf(\"********************************************************************************\");

gotoxy(1,2);
}
```