Line Drawing using Bresenham Algorithm with patterns such as simple,dash,dash-dot,thick
# include <stdio .h>
# include <stdio.h>
  # include <conio.h>
  # include <graphics.h>

  void main()
  {
    int dx,dy,x,y,p,x1,y1,x2,y2;
    int gd,gm;

    clrscr();

    printf("\n\n\tEnter the co-ordinates of first point : ");
    scanf("%d %d",&x1,&y1);
    printf("\n\n\tEnter the co-ordinates of second point : ");
    scanf("%d %d",&x2,&y2);

    dx = (x2 - x1);
    dy = (y2 - y1);

    p = 2 * (dy) - (dx);

    x = x1;
    y = y1;

    detectgraph(&gd,&gm);
    initgraph(&gd,&gm,"c:\\tc\\bgi");
    putpixel(x,y,WHITE);

    while(x <= x2)
    {
      if(p < 0)
      {
        x=x+1;
        y=y;
        p = p + 2 * (dy);
      }
      else
      {
        x=x+1;
        y=y+1;
        p = p + 2 * (dy - dx);
     }
     putpixel(x,y,WHITE);
   }
   getch();
   closegraph();
}
Output: