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I had an assignment, for which I got full marks, but am really upset about the code I have written. I feel it is too manual and repetitive. Please help me make it more optimized.

I am making many objects of StringTokenizer and using many static variables. I wish to reduce that, and instead of using declaring 10 Strings, I wish to do it fewer number of times and get better code.

The code basically uses a class Lab5BTmethods which is given by my professor. We had to do the following:

  1. Create a binary tree using the method createBinaryTree() from the given class file
  2. Traverse the tree in preOrder(), a method in the given class file
  3. Print the height() (method in the class file)
  4. Print the level order of the tree (method in class file)
  5. Print number of nodes in tree (method in the class file)
  6. Print the largest number in the tree, which we had to code it
  7. sumOfElements()
  8. searchfor(n)
  9. levelWithlargestNumberOfNodes() (I feel this is the worst in my code)

I am learning data structures and algorithms, which hugely deal with the complexity of code.

import java.util.*;
import java.text.*;
import java.io.*;

class CS6085BTolani 
{

    static Lab5BTMethods one = new Lab5BTMethods();
    static int array[] ;
    static int counter=0;
    static int level = 0;
    static int right = 0;
    static int left  = 0;
    static int numberOfNodesInLevel = 0;
    static int levelWithMaxNodes = -1;
    static File f1;
    static PrintWriter pw;

    public static void main(String[] args) throws Exception
    {
        new MyInfo().identity();
        one.createBinaryTree();
        array = new int[numberOfNodes(one.root)];
        System.out.println();
        System.out.println("Pre Order Travesal");
        one.preOrder(one.root);
        System.out.println("\n");
        System.out.println("Height of the Tree = "+one.height(one.root));

        System.out.print("\nThe Level Order of the Tree");
        one.displayTree(one.root);
        System.out.println("\n");
        System.out.println("Number of nodes in the tree : "+numberOfNodes(one.root));
        System.out.println("\nLargest Value in the tree : "+largest(one.root));
        System.out.println();
        System.out.println("Sum of Elements : " + sumOfElements(one.root));
        System.out.println();
        int x = 10;//search element
        System.out.println("Search for Number " + x +" : "+searchFor(one.root,x));
        System.out.println();
        levelWithLargestNumberOfNodes(one.root);
        System.out.println();
    }

    static int numberOfNodes(Lab5BTNode root)
    {
        if(root == null)
            return 0;
        else 
            return(numberOfNodes(root.right) + numberOfNodes(root.left) + 1);
    }
    static void toArray(Lab5BTNode root)
    {

        if(root!=null)
        {
            array[counter++] = root.element;
            toArray(root.left);
            toArray(root.right);
        }
    }
    static int largest(Lab5BTNode root)
    {
        int large = 0;
        counter=0;
        toArray(root);
        for (int i =0; i<array.length; i++) {
            if(array[i]>large){
                large = array[i];
            }
        }
        return large;
    }
    // program for Assignment B
    static int sumOfElements(Lab5BTNode root)
    {
        counter=0;
        toArray(root);
        int sum=0;
        for (int i = 0; i < array.length; i++) {
            sum = sum + array[i];
        }
        return sum;
    }
    static boolean searchFor(Lab5BTNode root, int n)
    {
        counter=0;
        toArray(root);
        for (int i =0; i<array.length; i++)
            if(array[i]==n)
                return true;
        return false;
    }
    static void levelWithLargestNumberOfNodes(Lab5BTNode root) throws Exception
    {

        f1 = new File("temp.txt");
        pw = new PrintWriter("temp.txt");
        boolean b1 = f1.createNewFile();
        //System.out.println(b1);
        if(!b1){
            for(int i = 0 ; i < (one.height(root)); i++)
            {
                printElementsOnALevel(one.root,i);
                pw.println();
            }
            pw.flush(); pw.close();
        }

        boolean b2 = f1.exists();
        //System.out.println(b2);

        if(b2)
        {
            Scanner sc = new Scanner(f1);
            int count = 0;
            String lev0="",lev1="",lev2="",lev3="",lev4="",lev5="",lev6="",lev7 = "",lev8 = "",lev9 = "",lev10 = "";
            while (sc.hasNextLine())
            {
                if(count==0)
                    lev0 = sc.nextLine();
                if(count==1)
                    lev1 = sc.nextLine();
                if(count==2)
                    lev2 = sc.nextLine();
                if(count==3)
                    lev3 = sc.nextLine();
                if(count==4)
                    lev4 = sc.nextLine();
                if(count==5)
                    lev5 = sc.nextLine();
                if(count==6)
                    lev6 = sc.nextLine();
                if(count==7)
                    lev7 = sc.nextLine();
                if(count==8)
                    lev8 = sc.nextLine();
                if(count==9)
                    lev9 = sc.nextLine();
                if(count==10)
                    lev10 = sc.nextLine();
                count++;
            }
            StringTokenizer tokens = new StringTokenizer(lev0," ");
            int firstcount = tokens.countTokens();
            //System.out.println(firstcount);

            StringTokenizer tokens1 = new StringTokenizer(lev1," ");
            int secondcount = tokens1.countTokens();

            StringTokenizer tokens2 = new StringTokenizer(lev2," ");
            int thirdcount = tokens2.countTokens();

            StringTokenizer tokens3 = new StringTokenizer(lev3," ");
            int fourthcount = tokens3.countTokens();

            StringTokenizer tokens4 = new StringTokenizer(lev4," ");
            int fifthcount = tokens4.countTokens();

            StringTokenizer tokens5 = new StringTokenizer(lev5," ");
            int sixthcount = tokens5.countTokens();

            StringTokenizer tokens6 = new StringTokenizer(lev6," ");
            int seventhcount = tokens6.countTokens();

            StringTokenizer tokens7 = new StringTokenizer(lev7," ");
            int eighthcount = tokens7.countTokens();

            StringTokenizer tokens8 = new StringTokenizer(lev8," ");
            int ninthcount = tokens8.countTokens();

            StringTokenizer tokens9 = new StringTokenizer(lev9," ");
            int tenthcount = tokens9.countTokens();

            StringTokenizer tokens10 = new StringTokenizer(lev10," ");
            int eleventhcount = tokens10.countTokens();

            int temp[] = {firstcount,secondcount,thirdcount,fourthcount
                ,fifthcount,sixthcount,seventhcount,eighthcount,ninthcount,tenthcount,eleventhcount};

                int maxValue = temp[0]; 

        for(int i=1;i < temp.length;i++)
        { 
            if(temp[i] > maxValue)
            { 
                maxValue = temp[i]; 

            }
        }System.out.println("Levels with max number of Nodes i.e "+maxValue+" nodes are as follows : " );

                if(maxValue == firstcount)
                    System.out.println(lev0);
                if(maxValue == secondcount)
                    System.out.println(lev1);
                if(maxValue == thirdcount)
                    System.out.println(lev2);
                if(maxValue == fourthcount)
                    System.out.println(lev3);
                if(maxValue == fifthcount)
                    System.out.println(lev4);
                if(maxValue == sixthcount)
                    System.out.println(lev5);
                if(maxValue == seventhcount)
                    System.out.println(lev6);
                if(maxValue == eighthcount)
                    System.out.println(lev7);
                if(maxValue == ninthcount)
                    System.out.println(lev8);
                if(maxValue == tenthcount)
                    System.out.println(lev9);
                if(maxValue == eleventhcount)
                    System.out.println(lev10);
            f1.delete();
        }

    }

    static void printElementsOnALevel(Lab5BTNode root, int lev)throws Exception
    {
        if(root == null) return;
        if(lev == 0) pw.print(root.element + " ");
        else if(lev>0){
            printElementsOnALevel(root.left, lev-1);
            printElementsOnALevel(root.right, lev-1);
        }
    }
}

class MyInfo
{
  String todaysDate = "06/OCT/2016";
  String assignmentNumber = "5B";

  public void identity(){
  // My info and class and assigmnegt date and all
    System.out.println("\n");
    System.out.println("Name : Mayur Tolani");
    System.out.println("Course : CS608");
    SimpleDateFormat dateformat3 = new SimpleDateFormat("dd/MMM/yyyy");
    Date assingmentDate = null;
    try{
        assingmentDate = dateformat3.parse(todaysDate); //Date printing, using the DATE class in java.
      } 
      catch (ParseException ex) {
          System.out.print(ex);
      }
    System.out.println("Assingment " +assignmentNumber+ "\nDone on : "+dateformat3.format(assingmentDate));
    System.out.println("--------------------------------------------------------");
  }
}
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0

1 Answer 1

Reset to default
2
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Employ the use of arrays

                while (sc.hasNextLine())
                {
                    if(count==0)
                        lev0 = sc.nextLine();
                    if(count==1)
                        lev1 = sc.nextLine();
                    if(count==2)
                        lev2 = sc.nextLine();
                    if(count==3)
                        lev3 = sc.nextLine();
                    if(count==4)
                        lev4 = sc.nextLine();
                    if(count==5)
                        lev5 = sc.nextLine();
                    if(count==6)
                        lev6 = sc.nextLine();
                    if(count==7)
                        lev7 = sc.nextLine();
                    if(count==8)
                        lev8 = sc.nextLine();
                    if(count==9)
                        lev9 = sc.nextLine();
                    if(count==10)
                        lev10 = sc.nextLine();
                    count++;
                }

You should refactor your 'lev0throughlev10` to utilize an array. This is effectively just a for loop and could be simplified to the following.

for (int i = 0; i <= count; count++) {
  // optional point of validation
  lev[i] = sc.nextLine();
}

Likewise here:

                StringTokenizer tokens = new StringTokenizer(lev0," ");
                int firstcount = tokens.countTokens();
                //System.out.println(firstcount);

                StringTokenizer tokens1 = new StringTokenizer(lev1," ");
                int secondcount = tokens1.countTokens();

                StringTokenizer tokens2 = new StringTokenizer(lev2," ");
                int thirdcount = tokens2.countTokens();

                StringTokenizer tokens3 = new StringTokenizer(lev3," ");
                int fourthcount = tokens3.countTokens();

                StringTokenizer tokens4 = new StringTokenizer(lev4," ");
                int fifthcount = tokens4.countTokens();

                StringTokenizer tokens5 = new StringTokenizer(lev5," ");
                int sixthcount = tokens5.countTokens();

                StringTokenizer tokens6 = new StringTokenizer(lev6," ");
                int seventhcount = tokens6.countTokens();

                StringTokenizer tokens7 = new StringTokenizer(lev7," ");
                int eighthcount = tokens7.countTokens();

                StringTokenizer tokens8 = new StringTokenizer(lev8," ");
                int ninthcount = tokens8.countTokens();

                StringTokenizer tokens9 = new StringTokenizer(lev9," ");
                int tenthcount = tokens9.countTokens();

                StringTokenizer tokens10 = new StringTokenizer(lev10," ");
                int eleventhcount = tokens10.countTokens();

Would be better as:

 StringTokenizer[] tokens = new StringTokenizer[10];
 int[] tokenCount = new int[tokens.length];
 for (int i = 0; i < tokens.length; i++) {
   tokens[i] = new StringTokenizer(lev[i], " ");
   tokenCount[i] = tokens[i].countTokens();
}

Notice how the use of arrays before lends itself to the following tokenizer loop.

This also applies to your max value logic. Interestingly, you loop through to find it, but then essentially 'loop' again to find out which one it was, why not simply store the position of the element (more about the use of arrays)?

So, your logic loop could be refactored thus:

int maxValue = tokenCount[0];
int maxPosition = 0;
for (int i = 1; i < tokenCount.length; i++) {
  if (tokenCount[i] > maxValue) {
    maxValue = tokenCount[i];
    maxPosition = i;
  }
}

So you may just proceed with System.out.println(lev[maxPosition]);

removing the need for:

                if(maxValue == firstcount)
                    System.out.println(lev0);
                if(maxValue == secondcount)
                    System.out.println(lev1);
                if(maxValue == thirdcount)
                    System.out.println(lev2);
                if(maxValue == fourthcount)
                    System.out.println(lev3);
                if(maxValue == fifthcount)
                    System.out.println(lev4);
                if(maxValue == sixthcount)
                    System.out.println(lev5);
                if(maxValue == seventhcount)
                    System.out.println(lev6);
                if(maxValue == eighthcount)
                    System.out.println(lev7);
                if(maxValue == ninthcount)
                    System.out.println(lev8);
                if(maxValue == tenthcount)
                    System.out.println(lev9);
                if(maxValue == eleventhcount)
                    System.out.println(lev10);
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