Program to draw a C-Curve of nth order

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

 void show_screen( );

 void C_curve(long double,long double,long double,long double,int);

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

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

       long double x=0;
       long double y=0;
       long double l=0;
       long double angle=0;

       int n=0;

       do
      {
         show_screen( );

         gotoxy(8,10);
         cout<<\"Starting Point of the Line : (x,y) :\";

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

         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<<\"Length of the Line : l : \";
         cin>>l;

         gotoxy(8,20);
         cout<<\"Angle of the Line with x-axis : \";
         cin>>angle;

         angle*=(M_PI/180);

         gotoxy(8,22);
         cout<<\"Enter the Order of C-Curve = n = \";
         cin>>n;

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

         setcolor(15);
           C_curve(x,y,l,angle,n);

         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;
    }


 //------------------------------  C_curve( )  ---------------------------//


 void C_curve(long double x,long double y,long double length,
                          long double angle,int n_order)
    {
       if(n_order>0)
      {
         length/=M_SQRT2;

         C_curve(x,y,length,(angle+M_PI_4),(n_order-1));

         x+=(length*cosl(angle+M_PI_4));
         y+=(length*sinl(angle+M_PI_4));

         C_curve(x,y,length,(angle-M_PI_4),(n_order-1));
      }

       else
      {
         setcolor(getcolor( ));
           Line((int)(x+0.5),(int)(y+0.5),
                 (int)(x+length*cosl(angle)+0.5),
                        (int)(y+length*sinl(angle)+0.5));
      }
    }


 //-------------------------------  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(\" C-Curve \");
       textbackground(8);

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

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

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

       gotoxy(1,2);
    }