Drawing a tree

Question

I need to actually "draw" out a tree. By draw I mean display it in a certain way according to an array. I basically have the tree structure the way I want it except for one thing. Right now my tree outputs like this:
+-Root
  +-SubB
    +-LEAF1
    +-LEAF2
  +-LEAF3
  +-SubA
    +-LEAF4
    +-LEAF5You can tell who's children belong to who. I however need to add vertical bars to connect pluses that aren't right under each other. My output SHOULD look like this:
+-Root
  +-SubB
  | +-LEAF1
  | +-LEAF2
  +-LEAF3
  +-SubA
    +-LEAF4
    +-LEAF5I'm not too sure how to go about adding in these vertical bars though. I imagine I should probably do it while I'm building the tree but I think it may be easier to just put them in the right place once I have what I already have.
Edited by: JFactor2004 on Nov 2, 2007 3:38 PM

Answer 1

Hey all, thanks for the insight. I had a burst of inspiration of my own while I was taking a break and came up with a solution. Its a little bit gross and basically does it in three steps but it works. Did I mention its gross...
import java.util.*;
import java.util.Map.Entry;
public class DrawTree
     public static class Node
          String name="";
          int myIndex;
          int nextIndex;
          int myLevel;
          ArrayList<Node> nexts = new ArrayList<Node>();
          public String toString()
               return name;
     ArrayList<Node> all = new ArrayList<Node>();
     ArrayList<Node> list = new ArrayList<Node>();
     public void linker(Node n)
          Iterator<Node> it = all.iterator();
          while(it.hasNext())
               Node temp = it.next();
               if(temp.nextIndex == n.myIndex)
                    all.get(all.indexOf(n)).nexts.add(all.get(all.indexOf(temp)));
                    linker(temp);
     public void adder(Node n,int level)
          if(n!=null)
               n.myLevel = level;
               list.add(n);
               Iterator<Node> it = n.nexts.iterator();
               while(it.hasNext())
                    Node temp = it.next();
                    adder(temp,level+1);
     public int correctIndex(Node n)
          String name = n.name;
          int i=0;
          while(i<name.length() && (name.charAt(i)==' '||name.charAt(i)=='|'))
               i++;
          return i;
     public boolean moreOnBranch(int index)
          for(int i=index+1;i<list.size();i++)
               if(list.get(i).myLevel==list.get(index).myLevel)
                    return true;
               if(list.get(i).myLevel<list.get(index).myLevel)
                    return false;
          return false;
     public void format(int index)
          int i = index+1;
          int place = correctIndex(list.get(index));
          String build = list.get(index).name.substring(0,place);
          String theRest = list.get(index).name.substring(place);
          build+="+-"+theRest;
          list.get(index).name=build;
          while(i<list.size() && list.get(i).myLevel>list.get(index).myLevel)
               if(moreOnBranch(index))
                    int spot = correctIndex(list.get(i));
                    String builder = list.get(i).name.substring(0,place);
                    String other = list.get(i).name.substring(place);
                    builder+="| "+other;
                    list.get(i).name=builder;
               else
                    int spot = correctIndex(list.get(i));
                    String builder = list.get(i).name.substring(0,place);
                    String other = list.get(i).name.substring(place);
                    builder+="  "+other;
                    list.get(i).name=builder;
               i++;
     public String[] draw(int[] parents, String[] names)
          //turn each pair into a Node and add it to a list of nodes
          Node root = null;
          for(int i=0;i<parents.length;i++)
               Node n = new Node();
               n.name = names;
               n.nextIndex = parents[i];
               n.myIndex = i;
               if(n.nextIndex == -1)
                    root = n;
               all.add(n);
          //find root, recurse through adding nexts
          linker(root);
          //preorder addition to list
          adder(root,0);;
          //put them in the right format
          for(int i=0;i<list.size();i++)
               format(i);
          String thingToReturn[] = new String[list.size()];
          for(int i=0;i<list.size();i++)
               thingToReturn[i]=list.get(i).name;
          return thingToReturn;