Breseham line drawing algorithm

#include<stdio.h>
#include<conio.h>
#include<graphics.h>
#include<math.h>
void main()
{
    int x1,y1,x2,y2,gd,gm,dx,dy;
    float p0,p1,xinc,yinc;
    detectgraph(&gd,&gm);
    initgraph(&gd,&gm,"c:\\tc\\bgi");
    printf("enter the coordinates");
    scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
    putpixel(x1,y1,WHITE);
    dx = x2-x1;
    dy = y2-y1;
    while(x1!=x2&&y1!=y2)
    {

        if(abs(dx)>=abs(dy))
        {
             p0 = 2*abs(dy)-abs(dx);
             p1=p0;
            if(p1<0)
            {
                xinc = dx/abs(dx);
                yinc = 0;
                p1=p0+2*abs(dy);
            }
            else
            {
                xinc=dx/abs(dx);
                yinc=dy/abs(dy);
                p1=p0+2*abs(dy)-2*abs(dx);
            }
        }
        if(abs(dy)>abs(dx))
        {
            p0=2*abs(dx)-abs(dy);
            p1=p0;
            if(p1<0)
            {
                xinc=dx/abs(dx);
                yinc=0;
                p1=2*abs(dx);
            }
            else if(p1>0)
            {
                xinc=dx/abs(dx);
                yinc=dy/abs(dy);
                p1=p0+2*abs(dx)-2*abs(dy);
            }
        }
        x1=(int)(x1+xinc+0.5);
        y1=(int)(y1+yinc+0.5);
        putpixel(x1,y1,WHITE);
        putpixel(x1,y1+1,WHITE);
        putpixel(x1,y1-1,WHITE);
        putpixel(x1,y1+2,WHITE);
        putpixel(x1,y1-2,WHITE);
    }
    getch();
}