Polymorphism and Random Numbers

Question

Im having issues correctly using random numbers in this program.All I want to do is: generate 4 random ints,and 3 random operators,then prints the results in a toString() method
import java.util.Random;
public class TestArithmetic2 {
    // evaluate (int / int) - (int * int)) = result
      //((8.0 / 8.0) - (2.0 * 5.0)) = -10.0
    public static void main(String[] args) {
        Node n = new RandomOps(
            new RandomOps(
            new RandomConst(), new RandomConst()),
            new RandomOps(new RandomConst(), new RandomConst()));
               public Character RandomOperator(){
                    Random random = new Random();
                    //char array with characters
                    char[] chars = new char[]{'+','-','*','/'};
                    //Generate a random number
                    int r = randomChar.nextInt(chars.length);
                    //Get char at random index
                    char randomOps = chars[r];
               public int RandomConstant(){
                    int randomConst = 1 + (int)(Math.random() * 20);
               public String toString(){
                    return "(" + "(" + lChild.eval() + "-" + rChild.eval() + ")" + ")" + "=" n.eval();
        System.out.println(""+ n.eval());
}

Answer 1

Opps.Sorry.Here's everything that should help it compile.
public class Node {
    public Node() {}
    public double eval() {
        System.out.println("Error: eval Node");
        return 0;
import java.util.Random;
public class TestArithmetic2 {
    // evaluate (int / int) - (int * int)) = result
      //((8.0 / 8.0) - (2.0 * 5.0)) = -10.0
    public static void main(String[] args) {
        Node n = new RandomOps(
            new RandomOps(
            new RandomConst(), new RandomConst()),
            new RandomOps(new RandomConst(), new RandomConst()));
               public Character RandomOperator(){
                    Random random = new Random();
                    //char array with characters
                    char[] chars = new char[]{'+','-','*','/'};
                    //Generate a random number
                    int r = randomChar.nextInt(chars.length);
                    //Get char at random index
                    char randomOps = chars[r];
               public int RandomConstant(){
                    int randomConst = 1 + (int)(Math.random() * 20);
               public String toString(){
                    return "(" + "(" + lChild.eval() + "-" + rChild.eval() + ")" + ")" + "=" n.eval();
        System.out.println(""+ n.eval());
public class Binop extends Node {
    protected Node lChild, rChild;
    public Binop(Node l, Node r) {
         lChild = l; rChild = r;
}