Implement unlimited Classification through iteration

Speaking of the infinitus classification, I believe many people know what it is and have done it before. I also believe that the most widely used method is to implement recursion.

Recently, I also want to create a menu with unlimited classification, but I don't want to use recursion. So I need to implement it in other ways, that is, iteration.

First, I need to define an entity model. Here is an example of an infinite province/city:

      ID { ;   PID { ;   Name { ; ; }              Level { ; ; }          }

Then write the method. here we need to take advantage of the features of stack first-in-first-out:

          List<Loaction> Soft(List<Loaction> data, = <Loaction> tree =  List<Loaction> level =  (task.Count >  flag =  ( i = ; i < data.Count; i++ l = (l.PID ====++--= (! (task.Count > =--

Finally, prepare the data-> call-> output:

          Main( data =  List<Loaction> Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  Loaction() { ID = , PID = , Name =  tree = Soft(data,  ( t  sb =  ( i = ; i < t.Level; i++  

Then the effect is as follows:

That's what it looks like ..... (END)