Why isn't this Math.random method working? - math

Question

Since Java doesn't allow to return two types in one method, I thought best way to do it is to use get methods.
Simply, I wanted computer to generate two random numbers, and if they were not the same I wanted it to print sum of them. If they were the same, I wanted it to roll once more and sum all of the rolls. Until here, it was okay, but then I wanted to see not only sum, but also the numbers that computer generated randomly before adding them up. Therefore, it had to be several return types.
But it prints 0 three times instead.
Can you help me with this? I want to learn what is wrong exactly with this code and if it can be done neater and cleaner? I know Java loves long ways..
Thank you.
class App {
public static int monopolyRoll(int side) {
double randomNumber = Math.random();
randomNumber = randomNumber * side;
randomNumber = randomNumber + 1;
int randomInt = (int) randomNumber;
return randomInt;
}
private int roll1 = monopolyRoll(6);
private int roll2 = monopolyRoll(6);
public int userRolls() {
if (roll1 != roll2) {
return roll1 + roll2;
} else {
int roll3 = monopolyRoll(6);
int roll4 = monopolyRoll(6);
return roll1 + roll2 + roll3 + roll4;
}
}
private static int first;
private static int second;
private static int third;
public App(int first, int second, int third) {
App.first = roll1;
App.second = roll2;
App.third = userRolls();
}
public static int getFirst() {
return first;
}
public static int getSecond() {
return second;
}
public static int getThird() {
return third;
}
public static void main(String[] args) {
int first = getFirst();
int second = getSecond();
int third = getThird();
System.out.println(first);
System.out.println(second);
System.out.println(third);
}
}

Answer 1

Math.random() works, but you never actually call it in your application. This is what your application does:
int first = getFirst();
int second = getSecond();
int third = getThird();
System.out.println(first);
System.out.println(second);
System.out.println(third);
That's it. Aside from the single return statements in those getter methods and the declared-but-never-assigned integers they return (so, zeroes), none of that other code ever executes.
I suspect this is coming from a bit of a misunderstanding on your part about the static keyword. By sprinkling around the static keyword until the code compiled, what you've done is create something that's syntactically correct but doesn't do anything :)
As a bit of a learning exercise, try moving all of the business logic out of the App class, leaving only the main() method as the application's entry point. And removing all static keywords from the new class you create. This should make the use of that class more clear.
Something like:
class Roller {
private int roll1;
private int roll2;
// other private variables
private int monopolyRoll(int side) {
// your code
}
// your other methods, also private and non-static
public Roller(int first, int second, int third) {
this.first = roll1;
this.second = roll2;
this.third = userRolls();
}
// and so on
}
The idea here is to make things instance-based (non-static) by default. Also make things private by default until explicitly needed to be accessed outside the class. Currently the only things your class needs to expose publicly are the constructor and the getters.
Then in the main() method you'll need to create an instance of your class to use it. Something like this:
Roller roller = new Roller(1, 2, 3);
int first = roller.getFirst();
int second = roller.getSecond();
int third = roller.getThird();
System.out.println(first);
System.out.println(second);
System.out.println(third);