Generate a new random number each time function is called in Javascript

Question

I am trying to learn javascript, I am playing with a game that picks a random number.

I would like to have 2 functions, random and guess. Random generates a new number between 1-10. Guess is where it checks if the number was guessed, if not re-runs the random function and generates a new number to try.

var x;
function random(){
    let x = Math.floor((Math.random() * 10) + 1);
    guess();
 }

function guess(x){
    if(x === 3){
        alert('you are correct!');
    }else{
        alert('try again');
        random();
    }
}

random();

This just alerts try again every time, i'm guessing because it's not generating a new number each time the function is called?

How can you create the random function so it generates a new number each time its called?

***** Correction, it appears to generate a new number but x is undefined within the guess function**

Answer 1

The x in the guess() is the x that gets passed to it as a parameter. I would remove the var x; declaration and pass a value when calling like guess(x)

function random(){
    const x = Math.floor((Math.random() * 10) + 1);
    guess(x);
 }

function guess(x){
    if(x === 3){
        alert('you are correct!');
    }else{
        alert('try again');
        random();
    }
}

random();

Answer 2

The guess function's signature says that it takes a parameter x, but you're not passing any value to the function when it's called, so it's assigning undefined to x when it runs guess, which will never equal 3. You can take 2 approaches to fix this. First, you could make x a global variable by getting rid of the let where you define x in the random function and removing x from guess's function signature, like so:

var x;

function random() {
  x = Math.floor((Math.random() * 10) + 1);
  guess();
}

function guess() {
  if (x === 3) {
    alert(x + '- you are correct!');
  }
  else {
    alert(x + '- try again');
    random();
  }
}

random();

Or, you could use x as a parameter for the guess function by removing the var x; global declaration and passing x to guess when you call it in the random function, like so:

function random() {
  let x = Math.floor((Math.random() * 10) + 1);
  guess(x);
}

function guess(x) {
  if (x === 3) {
    alert(x + '- you are correct!');
  }
  else {
    alert(x + '- try again');
    random();
  }
}

random();

I personally wouldn't even have a random function. I'd just define x within guess and call guess from within itself. And, I'd use randojs.com to make the randomness more readable. Here's how I'd do it:

function guess() {
  let x = rando(1, 10);
  if (x === 3) return alert(x + '- you are correct!');
  alert(x + '- try again');
  guess();
}

guess();

<script src="https://randojs.com/1.0.0.js"></script>

Note that the return statement would stop the execution of the function right then and there, so it wouldn't progress to the "try again" alert if the number was guessed correctly.