Variable expected error

Question

I am trying to make a bot that selects a random joke from an array list, but I seem to get an error that says:

Variable expected

My code so far is:

package com.delta.objects;
import java.util.ArrayList;
/**
 * Created by WILLIAM on 8/3/2015.
 */
public class JokeBot extends Bot {
 public ArrayList<Joke> jokesIKnow = null;
 public JokeBot(ArrayList<Joke> jokesIKnow) {
 this.jokesIKnow = jokesIKnow;
 }
 public void tellJoke(){
 Double randomNumDouble = new Double(Math.random() = jokesIKnow.size());
 int randomNum = randomNumDouble.intValue();
 }
 protected void sayJoke(Joke aJoke){
 talk(aJoke.getJokeSetup());
 talk(aJoke.getJokePunchline());
 }
}

the error comes up for:

Double randomNumDouble = new Double(Math.random() = jokesIKnow.size());

• Jeroen Vannevel: What do you expect that line of code to do?

Answer 1

Double randomNumDouble = new Double(Math.random() = jokesIKnow.size());

That's some very invalid syntax. You can't assign the return value of a method (in this case jokesIKnow.size() is a method which returns something) to anything except a variable. For example, this is legal:

int numberOfJokes = jokesIKnow.size();

Here you are trying to assign it to another method. Perhaps you mean to write Math.random(jokesIKnow.size()) which passes the variable into the random generator.

• Neuromeda: Your answer indirectly answered my question. I meant to put * instead of =, so now my code is: Double randomNumDouble = new Double(Math.random() * jokesIKnow.size()); I can understand the downvote however. That is a messy way to do it when your way is much more simple.