Printing a line in c

DDa algorithm  printing a line 

#include<stdio.h>                                                                  

#include<conio.h>                          

#include<graphics.h>                         

                                                                            

void main()

{

        int x,y,x1,y1,x2,y2,dx,dy,xi,yi,s,i;                                                                                                                        

        int gdriver=DETECT,gmode,gerror;

        initgraph(&gdriver,&gmode,"c:\\tc\\bgi");                   

        printf("\nEnter First Point (x1,y1):");        

        scanf("%d%d",&x1,&y1);                                    

        printf("\nEnter Second Point (x2,y2):");

        scanf("%d%d",&x2,&y2);                                    

        dx=x2-x1;               

        dy=y2-y1;

         if(abs(dx)>abs(dy))

         s=abs(dx);

         else

         s=abs(dy);

         xi=dx/s;

         yi=dy/s;

          x=x1;

          y=y1;

                         

          putpixel(x,y,7)       

          for(i=0;i<s;i++)

         {

                        x=x+xi;

                        y=y+yi;

                        putpixel(x,y,7);

          }

          getch();

          closegraph();                                                              

}

output