How to find node exists or not in binary tree in java?

Question

I tried this, but I get a compile time error. What am I missing? I should also return false if the item is not found.

public boolean search(Node root, Node node){
        if(root==node){
            return true;
        }
        if(root.getLeft()!=null){
            search(root.getLeft(), node);
        }

        if(root.getRight()!=null){
            search(root.getRight(), node);
        }
    }

Answer 1

You have a compilation error because you do not always return something:

    if(root.getLeft()!=null){
        search(root.getLeft(), node);
    }

    if(root.getRight()!=null){
        search(root.getRight(), node);
    }

This will fix the compilation error, but not the algorithm:

    if(root.getLeft()!=null){
       return search(root.getLeft(), node);
    }

    if(root.getRight()!=null){
        return search(root.getRight(), node);
    }

This should fix the algorithm:

    if(root.getLeft()!=null && search(root.getLeft(), node)) {
      return true;
    }

    if(root.getRight()!=null && search(root.getRight(), node)){
       return true;
    }
    return false;

Answer 2

public boolean search(Node root, Node node){
    if(root == node){
        return true;
    }
    boolean found = false;

    if(root.getLeft() != null ){
        found = search(root.getLeft(), node);
    }

    if(!found && root.getRight() != null )
    {
        found = search(root.getRight(), node);
    }

    return found;
}