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

 void show_screen( );

 void parametric_line(constint,constint,constint,constint);

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

       int x_1=0;
       int y_1=0;

       int x_2=0;
       int y_2=0;

       do
      {
         show_screen( );

         gotoxy(8,10);
         cout<<"Coordinates of Point-I (x1,y1) :";

         gotoxy(8,11);
         cout<<"ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ";

         gotoxy(12,13);
         cout<<"Enter the value of x1 = ";
         cin>>x_1;

         gotoxy(12,14);
         cout<<"Enter the value of y1 = ";
         cin>>y_1;

         gotoxy(8,18);
         cout<<"Coordinates of Point-II (x2,y2) :";

         gotoxy(8,19);
         cout<<"ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ";

         gotoxy(12,21);
         cout<<"Enter the value of x2 = ";
         cin>>x_2;

         gotoxy(12,22);
         cout<<"Enter the value of y2 = ";
         cin>>y_2;

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

         setcolor(15);
           parametric_line(x_1,y_1,x_2,y_2);

         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;
    }

 /*************************************************************************///-------------------------  parametric_line( )  ------------------------///*************************************************************************/void parametric_line(constint x_1,constint y_1,
                        constint x_2,constint y_2)
    {
       int color=getcolor( );

       float x=x_1;
       float y=y_1;
       float u=0;

       float dx=(x_2-x_1);
       float dy=(y_2-y_1);

       do
      {
         putpixel((int)(x+0.5),(int)(y+0.5),color);

         u+=0.001;

         x=(x_1+(u*dx));
         y=(y_1+(u*dy));
      }
       while(u<=1);
    }

 /*************************************************************************///--------------------------  show_screen( )  ---------------------------///*************************************************************************/void show_screen( )
    {
       restorecrtmode( );
       textmode(C4350);

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

       textbackground(1);
       cprintf(" Parametric Equation ");
       textbackground(8);

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

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

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

       gotoxy(1,2);
    }