procedure del_left(in/out:root,parent,node)
begin
     var albero: root,parent,nodo,new_parent,new_node
     new_parent:=parent
     new_node:=nodo.left
     if(parent!=NULL)then
        parent.left:=nodo.left
     else
        root:=nodo.left
     endif
     while(new_node!=NULL)do
           new_parent:=new_node
           new_node:=new_node.right
     endwhile
     if(nodo.left!=NULL)then
        if(new_parent!=NULL)then
           new_parent.right:=nodo.right
        else
           root:=nodo.right
        endif
     else
         if(parent!=NULL)then
            parent.right:=nodo.right
         else
            root:=nodo.right
         endif
     endif
end del_left