How to read a txt file and print it as a tree form?

Here is the text :

ABC
1Central
11Mendy
111-Irving
112-Grey
113-LDS
2Hill
21Tabler
211-Tosc
212-TAC
213-Hand
22Roth
3West
31WestApartments
32-GLS Center
4-BasementClub
Read and print it as a tree form:

->ABC //cursor is automatically at root

+Central

+Mendy

-Irving

-Grey

-LDS

+Hill

+Tabler

-Tosc

-TAC

-Hand

+Roth

+West

+WestApartments

-GLS Center

-BasementClub

public static NetworkTree readFromFile(String filename)

Generates the NetworkTree based on the file name that is passed in.

public static void writeToFile(NetworkTree tree, String filename)

Generates a text file that reflects the structure of the NetworkTree.

The format of the tree of the file should match the format of the input file.