How can I return a boolean while traversing a BinaryTree recursivly and checking for a specific Node with matching Value?

Question

I'm currently working on Tree Data Structures and Recursion in Java. My Plan was to have a recursive method, which traverses the Tree and checks if any Node in the Tree has this certain value. If so, the method returns true, else the method returns false. For a better understanding I added print Statements. The Issue I have is that, the method retuns false even if a node exsits with that certain value. It only returns true, if the value matches the root value. My Method looks like this:

//Calling this method in the main function
    public boolean checkForValue(int value) {
        return checkForValue(value, root);
    }
    
    private boolean checkForValue(int value, TreeNode current) {
        //Checking if the current value is null, if so return false
        if(current == null) {
            return false;
        } else {
            //if the current nodes value matches the value we are looking for
            // it should return true
            if(current.value == value) {
                
                System.out.println("Found a Node with same value");
                
                return true;
            }
            //if it wasnt the value, call the method recusrivly
            //with the current.right node
             else {
                System.out.println("Value didnt matched the current Node");
                checkForValue(value, current.right);
                checkForValue(value, current.left);
                return false;
                
            }
        }
        
    }

My Main Method looks like this:

public static void main(String[] args) {
            Tree tree = new Tree();
            tree.add(new TreeNode(20));
            tree.add(new TreeNode(30));
            tree.add(new TreeNode(10));
            tree.add(new TreeNode(15));
            tree.add(new TreeNode(5));
            tree.add(new TreeNode(40));
            tree.add(new TreeNode(29));
            System.out.println(tree.checkForValue(40));
}

It prints out false, although the Tree has a Node with Value of 40. My Console looks like this after running it:

1. Value didnt matched the current Node
2. Value didnt matched the current Node
3. Value didnt matched the current Node
4. Value didnt matched the current Node
5. Value didnt matched the current Node
6. Found a Node with same value
7. Value didnt matched the current Node

After finding the Node (line 6) it should just return true and not continue (line 7). How can i make sure that I stop, if I found the value?

Answer 1

You are ignoring the result of your recursive calls.

Rather than doing:

checkForValue(value, current.right);  // Result ignored.
checkForValue(value, current.left);   // Result ignored.
return false;                         // Always returned.

instead do:

return checkForValue(value, current.right)
    || checkForValue(value, current.left);

This will only descend into the left branch if the right branch resulted in false.