CODEWITHSUNDEEP
javatree
Ryan Smith
Ryan Smith

Reputation: 709

How to visually print a NON binary tree?

I made a basic tree where all the nodes have a name and a set of children.

public class Tree {
    String data;
    Tree parent = null;
    HashSet children = new HashSet();

    public Tree(String nodeName) {
        this.data = nodeName;
    }

    public void parent(Tree parent) {
        this.parent = parent
    }

    public void addAChild(Tree child) {
        this.children.add(child);
        child.parent(this);
    }

And to use this class

Tree a = new Tree("root");
Tree b = new Tree("n1");
Tree c = new Tree("n2");
Tree d = new Tree("n3");
Tree e = new Tree("n4");
Tree f = new Tree("n5");

a.addAChild(b);
a.addAChild(c);
a.addAChild(d);

d.addAChild(e);
e.addAChild(f);

This makes sense to me but I'd like a visual representation of the tree so that I can quickly test to see if the children and nodes are in the right place.

I'm trying to make the output look like this:enter image description here

Or something similar.

Upvotes: 3

Views: 4757

Answers (2)

Russell Senior
Russell Senior

Reputation: 23

This method works in python, and is recursive. Basically, it prints the name of each node, increases the indent and then calls the function on each child of each node. You will have to add an if statement before the for loop to determine if you are at the end of the branch so it doesn't call the function again.

Add it to your tree class. 

 def display(self,indent=0):
    print( (' '*indent)+self.name)        
    for c in self.children:
      c.display(indent+1)

Upvotes: 0

Cinnam
Cinnam

Reputation: 1922

A quick and dirty way of printing the tree would involve adding a method like this to your Tree class:

public void print(int level) {
    for (int i = 1; i < level; i++) {
        System.out.print("\t");
    }
    System.out.println(data);
    for (Tree child : children) {
        child.print(level + 1);
    }
}

level represents the level of the node in the tree, which is defined as 1 + (the number of connections between the node and the root). It dictates how much the node will be indented in the output.

Then you can print the tree by printing the root (the level of the root is 1):

a.print(1);

Getting output like this:

root
    n1
    n2
    n3
        n4
            n5

Upvotes: 6

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