Question

Write a java application to read in an attached CSV file and store the data items within a Binary Search Tree.

Answer 1

Code:

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

//File name CSVToBST.java
public class CSVToBST
{

   public static void main(String[] args) {
       // Creates an Object to BST Class
       BST b = new BST();

       //You can take file name from the user using
       /**
           Scanner in = new Scanner(System.in);
           File file = nextLine();
           */
      File file = new File("example.csv");
      //Creates a scanenr for file
      Scanner input;

      try{
          //assign the Scanner with file.
          input = new Scanner(file);
          //Until the end of file do the following.
          while(input.hasNext())
          {
              //Read a line
              String line= input.next();
              //Split the line at , which returns a Array of strings
              String[] values = line.split(",");
              //For all strings insert into the BST.
              for (String i : values) {
                  //While inserting convert the given string to integer.
                  b.insert(Integer.parseInt(i));
              }
          }
          //Close the input stream.
          input.close();
      }
      //If exception raises handle it.
      catch(FileNotFoundException e)
      {
          System.out.println("No such file found!!");
      }
      //To display the constructed BST.
      System.out.println("Obtained BST is");
      b.display();
   }
}

//To hold the BST data
class Node
{
   //properties data to hold data
   //left , right to holds addresses of left and right nodes.
   int data;
   Node left,right;

   //initialize the node with the given data.
   public Node(int data)
   {
       this.data=data;
       left=right=null;
   }
}

//Class to construct BST
class BST
{

   //A root to hold the root address
   private Node root;

   //Constructer to initialize root.
   public BST()
   {
       root = null;
   }

   //method insert to insert the passed argumetn x.
   public void insert(int x)
   {
       //use the utility function to insert the value.
       root = insert(this.root,x);
   }

   //a private utility function to insert the value.
   private Node insert(Node cur,int x)
   {
       //if the current node is null create new node and return.
       if(cur == null)
       {
           return new Node(x);
       }
       //if the value in current node is grater then the x insert in the left subtree.
       if(cur.data > x)
       {
           cur.left = insert(cur.left, x);
       }
       //in other case insert in the right subtree.
       else
       {
           cur.right = insert(cur.right, x);
       }
       //finally return the current (cur).
       return cur;
   }

   //function to display the tree inorder
   public void display()
   {
       if(this.root == null)
       {
           System.out.println("No tree found");
       }
       System.out.print("Inorder:");
       inorder(this.root);
       System.out.println();
       System.out.print("Preorder:");
       preorder(this.root);
   }

   //A private utility function to display Tree inorder.
   private void inorder(Node cur)
   {
       if(cur != null)
       {
           inorder(cur.left);
           System.out.print (cur.data+" ");
           inorder(cur.right);
       }
   }

   //A private utility function to display Tree preorder.
   private void preorder(Node cur)
   {
       if(cur != null)
       {
           System.out.print (cur.data+" ");
           preorder(cur.left);
           preorder(cur.right);
       }
   }
}

Input:

example.csv:

1,5,3,6,7,2 9,10,4,e,

Output:

Obtained BST is Inorder:0 1 2 3 4 5 6 7 8 9 18 Preorder:1 0 5 3 2 467 9 8 10

Hope your problem solved.

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