Bresenham's Algorithm

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

void main()
{
   int x1, y1, x2, y2;
   int gdriver = DETECT, gmode;
   clrscr();
   cout << "Enter the coordinates : ";
   cout << "\nx1 : ";
   cin >> x1;
   cout << "\ny1 : ";
   cin >> y1;
   cout << "\nx2 : ";
   cin >> x2;
   cout << "\ny2 : ";
   cin >> y2;

   int dx = abs(x1 - x2), dy = abs(y1 - y2);
   int p = 2 * dy - dx;
   int twoDy = 2 * dy, twoDyDx = 2 * (dy - dx);
   int x, y, xEnd;
   cout << "\nSlope is : " << (float)dy/dx;

   if((((float)dy/dx) >= 1) || (((float)dy/dx) == 0))
   {
      cout << "\nSlope m must be 0 < m < 1";
      getch();
      return;
   }

   int StoreX[50], StoreY[50], i = 1;
   cout << "\nPress Enter to continue...";
   getch();
   initgraph(&gdriver, &gmode, "F:\\TC\\BGI");
   if(x1 > x2)
   {
      x = x2;
      y = y2;
      xEnd = x1;
   }
   else
   {
      x = x1;
      y = y1;
      xEnd = x2;
   }
   StoreX[0] = x;
   StoreY[0] = y;
   putpixel(x, y, RED);
   while(x < xEnd)
   {
      x++;
      if(p < 0)
        p += twoDy;
      else
     {
        y++;
        p += twoDyDx;
     }
     StoreX[i] = x;
     StoreY[i] = y;
     i++;
     putpixel(x, y, RED);
   }
   outtextxy(100, 10, "Press Enter pls");
   getch();
   closegraph();
   ofstream fout;
   fout.open("Bresen.txt");
   for(int k = 0; k < i; k++)
   {
      fout << StoreX[k] << setw(2) << StoreY[k] << endl;
   }
   fout.close();
}