CSC403: More Size: Student code [10/10]

    public int size () {
        if (root == null) return 0;
        int total = 1 + size (root, 0);
        return total; // do not count self at the start
    }
    private static int size (Node x, int count) {
        // called when it finds the end
        int total = count, left = 0, right = 0; // likely can use less space - see about condensing
        if (x == null) return 0; // return 0 when the node is null - thus finding the end!
        else { // not at the end when this is called
            // if left has more, add them up and return them
            if (x.left != null) {
                left++; // increment
                left += size (x.left, left); // should add...
            }
            if (x.right != null) {
                right++;
                right += size (x.right, right);
            }
            // if right has more, add them up and return them
        }
        total = left + right;
        // return result
        return total;
    }

Is this correct?

Can it be improved?

Get rid of comments:

    public int size () {
        if (root == null) return 0;
        int total = 1 + size (root, 0);
        return total;
    }
    private static int size (Node x, int count) {
        int total = count, left = 0, right = 0;
        if (x == null) return 0;
        else {
            if (x.left != null) {
                left++;
                left += size (x.left, left);
            }
            if (x.right != null) {
                right++;
                right += size (x.right, right);
            }
        }
        total = left + right;
        return total;
    }

Unnecessary else. Tighten mutators.

    public int size () {
        if (root == null) return 0;
        int total = 1 + size (root, 0);
        return total;
    }
    private static int size (Node x, int count) {
        int total = count, left = 0, right = 0;
        if (x == null) return 0;
        if (x.left != null) left += 1 + size (x.left, left);
        if (x.right != null) right += 1 + size (x.right, right);
        total = left + right;
        return total;
    }

Get rid of some unnecessary variables and put declaration closer to use.

    public int size () {
        if (root == null) return 0;
        return 1 + size (root, 0);
    }
    private static int size (Node x, int count) {
        if (x == null) return 0;
        int total = count;
        if (x.left != null) total += 1 + size (x.left, left);
        if (x.right != null) total += 1 + size (x.right, right);
        return total;
    }

Oops! A bug.

    public int size () {
        if (root == null) return 0;
        return 1 + size (root, 0);
    }
    private static int size (Node x, int count) {
        if (x == null) return 0;
        int total = 0;
        if (x.left != null) total += 1 + size (x.left, left);
        if (x.right != null) total += 1 + size (x.right, right);
        return total;
    }

Notice that the parameter is not used!

    public int size () {
        if (root == null) return 0;
        return 1 + size (root);
    }
    private static int size (Node x) {
        if (x == null) return 0;
        int total = 0;
        if (x.left != null) total += 1 + size (x.left);
        if (x.right != null) total += 1 + size (x.right);
        return total;
    }