incompatible types: int cannot be converted to T

I’m getting this error, here is the necessary code. Assume the methods not here work correctly. Any help would be awesome. (I am coding on a text file in Ubuntu btw)

Here is the error message: (after compiling)

BinarySearchTree.java:132: error: incompatible types: int cannot be converted to T insert(y); ^ where T is a type-variable: T extends Comparable<? super T> declared in class BinarySearchTree Note: Some messages have been simplified; recompile with -Xdiags:verbose to get full output 1 error

Verbose error message:

BinarySearchTree.java:132: error: no suitable method found for insert(int) insert(y); ^ method BinarySearchTree.insert(T) is not applicable (argument mismatch; int cannot be converted to T) method BinarySearchTree.insert(T,BinaryNode) is not applicable (actual and formal argument lists differ in length) where T is a type-variable: T extends Comparable<? super T> declared in class BinarySearchTree 1 error

Here is my code:

import java.util.Scanner;
import java.util.Queue;
import java.util.LinkedList;

public class BinarySearchTree<T extends java.lang.Comparable<? super T>>
{

    private static class BinaryNode<T>
    {
        private T element; // The data in the node
        private BinaryNode<T> left; // Left child
        private BinaryNode<T> right; // Right child

        // Constructors
        BinaryNode( T theElement )
        {
            this( theElement, null, null );
        }

        BinaryNode( T theElement, BinaryNode<T> lt, BinaryNode<T> rt )
        {
            element = theElement;
            left = lt;
            right = rt;
        }
    }

    private BinaryNode<T> root; //root node of the tree

    // Constructor
    public BinarySearchTree( )
    {
        root = null;
    }

    /***************************************************
    * FUNCTION isEmpty: isEmpty *
    * checks if the tree is empty *
    * INPUT PARAMETERS: none *
    * none *
    * OUTPUT: boolean *
    * true if the tree is empty, false otherwise *
    ****************************************************/
    public boolean isEmpty( )
    {
        return root == null;
    }

    private BinaryNode<T> findMin( BinaryNode<T> t )
    {
        if( t == null )
            return null;
        else if( t.left == null )
            return t;
        return findMin( t.left );
    }

    /***************************************************
    * FUNCTION insert: insert *
    * inserts an item into the tree *
    * INPUT PARAMETERS: x *
    * x - the item to be added to the BST *
    * OUTPUT: none *
    * none *
    ****************************************************/
    public void insert( T x )
    {
        root = insert( x, root );
    }

    /***************************************************
    * FUNCTION insert: insert helper method *
    * inserts an item into the tree *
    * INPUT PARAMETERS: x, t *
    * x - the item to be added to the BST, subtree to be inserted in *
    * OUTPUT: BinaryNode<T> *
    * node to be set *
    ****************************************************/
    public  BinaryNode<T> insert( T x, BinaryNode<T> t )
    {
        if( t == null )
            return new BinaryNode<T>( x, null, null );

        int compareResult = x.compareTo( t.element );

        if( compareResult < 0 )
        {
            t.left = insert( x, t.left );
        }
        else if( compareResult > 0 )
        {
            t.right = insert( x, t.right );
        }
        else
        ; // Duplicate; do nothing
        return t;
    }

    /***************************************************
    * FUNCTION insertList: Option 1 *
    * parses a string and insert the values contained in it *
    * INPUT PARAMETERS: csv *
    * csv - comma seperated list of integers *
    * OUTPUT: none *
    * none *
    ****************************************************/
    public void insertList(String csv)
    {
        String[] inputValues = csv.split(",") ; // Numbers are seperated by comma as instructed
        for (String x : inputValues)
        {
            int y = Integer.parseInt(x);
            insert(y);
        }
    }
}

Answer

You have a generic parameter so it will be logically correct for you to create a new tree when reading CSV.

This also means insertList(...) should become static and now be invoked like BinarySearchTree<Integer> tree = BinarySearchTree.insertList(...)

Here is the code:

    public static void insertList(String csv)
    {
        String[] inputValues = csv.split(",") ; // Numbers are seperated by comma as instructed
        BinarySearchTree<Integer> tree = new BinarySearchTree<>();
        for (String x : inputValues)
        {
            int y = Integer.parseInt(x);
            tree.insert(y);
        }
    }

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Answer