Commit f3ab1023 authored by Ari Trachtenberg's avatar Ari Trachtenberg
Browse files

Nicer pretty-printing of BST.

parent 6047caf8

src/edu/bu/ec504/hw2/BST.java

+5 −20
Original line number Diff line number Diff line
@@ -89,46 +89,31 @@ public class BST<keyType extends Comparable<keyType> > { 
     * Return the BST rooted at this node as a human-readable string

     */

    final public String toString() {

        return toString(0);

        return toString("|");

    }



    /**

     * Return the BST rooted at this node as a human-readable string,

     * indented by <code>depth</code> characters

     *

     * @param depth How many characters to indent.

     * @param prefix The current prefix for the subtree being printed

     */

    final String toString(int depth) {

    final String toString(String prefix) {

        String result = "";



        // output the key

        result += key + "\n";



        // recurse

        if (left != null)

            result += repeatDelim(depth) + "L" + left.toString(depth + 1);

        if (right != null)

            result += repeatDelim(depth) + "R" + right.toString(depth + 1);



        result += prefix + "->" + (left == null ? "\n" : left.toString(prefix.concat("  |")));

        result += prefix + "->" + (right == null ? "\n":right.toString(prefix.replace("  |","   ").concat("  |")));

        return result;

    }



    /**

     * @return a string containing the repetition of the {@link #DELIM} character <code>depth</code> times.

     */

    private String repeatDelim(int depth) {

        StringBuilder result = new StringBuilder(depth);

        for (int ii = 0; ii < depth; ii++)

            result.append(DELIM);

        return result.toString();

    }





    // FIELDS

    protected keyType key; // the key stored by this node

    protected BST<keyType> left;    // the left child of this node

    protected BST<keyType> right;   // the right child of this node



    // CONSTANTS

    final char DELIM = '-'; // a delimiter for printing

}

src/edu/bu/ec504/hw2/Main.java

+7 −3
Original line number Diff line number Diff line
@@ -6,8 +6,12 @@ import java.util.Arrays; 
class Main {



    public static void main(String[] args) {

        ArrayList<Integer> numbers = new ArrayList<>(Arrays.asList(1, 3, 2, 5, 4));

        BST<Integer> test = new BST<>(numbers);

        System.out.println("Your BST is:\n"+test);

        ArrayList<Integer> intElements = new ArrayList<>(Arrays.asList(3,1,4,1,5,9,2,6));

        ArrayList<String> strElements = new ArrayList<>(Arrays.asList("Hi","Aardvark","Buy","me"));

        BST<Integer> intTest = new BST<>(intElements);

        BST<String> strTest = new BST<>(strElements);



        System.out.println("Your int BST is:\n"+intTest);

        System.out.println("Your string BST is:\n"+strTest);

    }

}