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JavaScript JavaScript Basics (Retired) Working With Numbers Create a random number

Bart Christoffersen
Bart Christoffersen
759 Points
Posted by Bart Christoffersen
Bart Christoffersen
759 Points

Had an idea and can't get it to work

I had a hairbrain idea to try to make my own little program but I can't get it to work and wondered if I could get some help trying to apply some of the principles I have picked up.

All I get in the console is the number 0.

//I want to roll a die and see the sum of all the times it takes to get a 0, which will be a jackpot and alert the user that it took them X number of times to get the jackpack. I figure that landing directly on the number 0 in Math.random are slim. So, I wanted to make a game of it.

//create the array that will store the history of die rolls
var rollHistory = [];

//create variable to hold the total die rolls counter
var totalDieRolls = 0;

//create variable to hold the die roll parameter
var dieRoll = 1;

//loop function until you roll a 0, then display the number of times it looped to get to roll zero
var loop = function(){
  while(dieRoll > 0) {

    //generate a random number
    var randomNumber = Math.random();
    console.log("Random number = " + randomNumber);

    //return an integer between 0 and 6
    var dieRoll = Math.ceil(randomNumber * 6);
    console.log("Random die roll = " + dieRoll);

    rollHistory.push(dieRoll);
    console.log(rollHistory);

    totalDieRolls++;
    console.log(totalDieRolls);
  }
}

loop();
console.log(totalDieRolls);
alert("It took " + totalDieRolls + "to land the jackpot!!!")

I was trying to debug it by keeping an eye on the console (thus all the console.log()). But I get only the one response.

2 Answers

Rand Seay
Rand Seay
13,975 Points
Rand Seay
Rand Seay
13,975 Points

I think you are scoping your dieRoll variable incorrectly. If you replace var dieRoll with simply dieRoll inside your loop, then the code runs and the console goes crazy (which I think you are intending). 

//return an integer between 0 and 6
//var dieRoll = Math.ceil(randomNumber * 6);
   dieRoll = Math.ceil(randomNumber * 6);
   console.log("Random die roll = " + dieRoll);

Just so you know, this isn't far from an endless loop, and can freeze up your browser (Source: I did it).

Bart Christoffersen
Bart Christoffersen
759 Points
Bart Christoffersen
Bart Christoffersen
759 Points

Ya, I had to kill it a lot. I wonder if the odds are just so low to get Math.random() to return 0, cause when i fixed it, it still loops. But when it does go, I don't get anything in the log telling me what it was doing. Maybe it was an effort in futility, but thought it would be a fun exercise. Thanks for the help.

Jarold Wong
Jarold Wong
7,766 Points
Jarold Wong
Jarold Wong
7,766 Points

Hi there, I think first thing you need to do is move the variable declarations outside the loop.

var loop = function(){
  var randomNumber = Math.random();
  var dieRoll = Math.ceil(randomNumber * 6);

  while(dieRoll > 0) {

    //generate a random number
    randomNumber = Math.random();
    console.log("Random number = " + randomNumber);

    //return an integer between 0 and 6
    dieRoll = Math.ceil(randomNumber * 6);