void main()
{
int driver,mode;
int xa,ya,xb,yb,c;
int dx,dy,steps,k;
float fx,fy,x,y;
int wx,wy;
driver=DETECT;
mode=0;
initgraph(&driver,&mode,"");
printf("please enter the start point:/n");
printf(" xa= ");
scanf("%d",&xa);
printf(" ya= ");
scanf("%d",&ya);
printf("please enter the end point:/n");
printf(" xb= ");
scanf("%d",&xb);
printf(" yb= ");
scanf("%d",&yb);
