int pcount=npoints(0);
if(@ptnum==pcount-2){
vector last_pos=point(0,"P",pcount-1);
@P.x=last_pos.x;
@P.z=last_pos.z;
}else if(@ptnum==1){
vector first_pos=point(0,"P",0);
@P.x=first_pos.x;
@P.z=first_pos.z;
}
要会读！要会读！
