class Vec3d {
    private double x;
    private double y;
    private double z;

    public Vec3d() {
    }

    public Vec3d(Vec3d arg) {
        set(arg);
    }

    public Vec3d(double x, double y, double z) {
        set(x, y, z);
    }

    public Vec3d copy() {
        return new Vec3d(this);
    }

    /**
     * Convert to single-precision
     */
    public Vec3f toFloat() {
        return new Vec3f((float) x, (float) y, (float) z);
    }

    public void set(Vec3d arg) {
        set(arg.x, arg.y, arg.z);
    }

    public void set(double x, double y, double z) {
        this.x = x;
        this.y = y;
        this.z = z;
    }

    /**
     * Sets the ith component, 0 &lt;= i &lt; 3
     */
    public void set(int i, double val) {
        switch (i) {
            case 0:
                x = val;
                break;
            case 1:
                y = val;
                break;
            case 2:
                z = val;
                break;
            default:
                throw new IndexOutOfBoundsException();
        }
    }

    /**
     * Gets the ith component, 0 &lt;= i &lt; 3
     */
    public double get(int i) {
        switch (i) {
            case 0:
                return x;
            case 1:
                return y;
            case 2:
                return z;
            default:
                throw new IndexOutOfBoundsException();
        }
    }

    public double x() {
        return x;
    }

    public double y() {
        return y;
    }

    public double z() {
        return z;
    }

    public void setX(double x) {
        this.x = x;
    }

    public void setY(double y) {
        this.y = y;
    }

    public void setZ(double z) {
        this.z = z;
    }

    public double dot(Vec3d arg) {
        return x * arg.x + y * arg.y + z * arg.z;
    }

    public double length() {
        return Math.sqrt(lengthSquared());
    }

    public double lengthSquared() {
        return this.dot(this);
    }

    public void normalize() {
        double len = length();
        if (len == 0.0) {
            return;
        }
        scale(1.0f / len);
    }

    /**
     * Returns this * val; creates new vector
     */
    public Vec3d times(double val) {
        Vec3d tmp = new Vec3d(this);
        tmp.scale(val);
        return tmp;
    }

    /**
     * this = this * val
     */
    public void scale(double val) {
        x *= val;
        y *= val;
        z *= val;
    }

    /**
     * Returns this + arg; creates new vector
     */
    public Vec3d plus(Vec3d arg) {
        Vec3d tmp = new Vec3d();
        tmp.add(this, arg);
        return tmp;
    }

    /**
     * this = this + b
     */
    public void add(Vec3d b) {
        add(this, b);
    }

    /**
     * this = a + b
     */
    public void add(Vec3d a, Vec3d b) {
        x = a.x + b.x;
        y = a.y + b.y;
        z = a.z + b.z;
    }

    /**
     * Returns this + s * arg; creates new vector
     */
    public Vec3d addScaled(double s, Vec3d arg) {
        Vec3d tmp = new Vec3d();
        tmp.addScaled(this, s, arg);
        return tmp;
    }

    /**
     * this = a + s * b
     */
    public void addScaled(Vec3d a, double s, Vec3d b) {<FILL_FUNCTION_BODY>}

    /**
     * Returns this - arg; creates new vector
     */
    public Vec3d minus(Vec3d arg) {
        Vec3d tmp = new Vec3d();
        tmp.sub(this, arg);
        return tmp;
    }

    /**
     * this = this - b
     */
    public void sub(Vec3d b) {
        sub(this, b);
    }

    /**
     * this = a - b
     */
    public void sub(Vec3d a, Vec3d b) {
        x = a.x - b.x;
        y = a.y - b.y;
        z = a.z - b.z;
    }

    /**
     * Returns this cross arg; creates new vector
     */
    public Vec3d cross(Vec3d arg) {
        Vec3d tmp = new Vec3d();
        tmp.cross(this, arg);
        return tmp;
    }

    /**
     * this = a cross b. NOTE: "this" must be a different vector than
     * both a and b.
     */
    public void cross(Vec3d a, Vec3d b) {
        x = a.y * b.z - a.z * b.y;
        y = a.z * b.x - a.x * b.z;
        z = a.x * b.y - a.y * b.x;
    }

    @Override
    public String toString() {
        return "(" + x + ", " + y + ", " + z + ")";
    }
}

        x = a.x + s * b.x;
        y = a.y + s * b.y;
        z = a.z + s * b.z;
    
<no_super_class>