Counting nodes in a binary tree according to a given criteria (recursively)

Question

I want to count the number of failed students who got a grade under 60 recursively using a binary search tree in java. I don't know if my method Is correct. find the helper method to be used in the public wrapper method after

    private int NumberfailStudents(int numoffailed, BNode current) {
        // BaseCase
        if (current == null) {

            return 0 + numofpassed;

        } else {

            if (current.data.getGrades() < 60) {
                return ++numoffailed;
            }

            if (current.left != null) {
                return NumberfailStudents(numoffailed, current.left);
            }
            if (current.right != null) {
                return NumberfailStudents(numoffailed, current.right);
            }

        }

        return numoffailed;

    }

Answer 1

If the if-condition that checking the current is null should return numoffailed not numofpassed

I have updated the NumberFailStudents to match the naming convention

    private int NumberFailStudents(int numOfFailed, BNode current) {
        if (current == null)
            return numOfFailed;

        if (current.data.getGrades() < 60)
            ++numOfFailed;

        if (current.left != null)
            numOfFailed = NumberFailStudents(numOfFailed, current.left);

        if (current.right != null)
            numOfFailed = NumberFailStudents(numOfFailed, current.right);

        return numOfFailed;
    }