DigitalDifferentialAnalyzer.CPP

//Digital Differential Analyzer

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

struct point {
   float x;
   float y;
};

void main() {
clrscr();

   int gd = DETECT,gm;
   initgraph(&gd,&gm,"C:\\TC\\BGI");

   point beg, end, Line;
   float slope;
   int j, i;

   cout<<"Enter co-ordinates of initial point: ";
   cin>>beg.x>>beg.y;
   cout<<"Enter co-ordinates of last point: ";
   cin>>end.x>>end.y;
   Line = beg;

   ////////////////////////////////////////////////

   line(20, 25, 20, 454); //x-axis
   line(15, 449, 619, 449); //y-axis

   ////////////////////////////////////////////////

   slope = fabs((end.y-beg.y)/(end.x-beg.x));
   if(slope <= 1) {
     for(i=0; i<int(end.x-beg.x); i++) {
      putpixel(Line.x, 449-Line.y, GREEN);
      Line.x += 1;
      Line.y += slope;
     }
   } else {
     for(i=0; i<int(end.y-beg.y); i++) {
      putpixel(Line.x, 449-Line.y, GREEN);
      Line.x += 1/slope;
      Line.y += 1;
     }
   }

getch();
closegraph();

}