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JavaScript JavaScript Basics (Retired) Creating Reusable Code with Functions Random Number Challenge

Anthony Rice
Anthony Rice
7,976 Points
Posted by Anthony Rice
Anthony Rice
7,976 Points

Math.round as an alternative to Math.floor or Math.ceil?

I was just wondering if using Math.round is a viable alternative to using the Math.round or Math.floor functions for creating a random number generator. My code is as follows

function randomNumber(min, max) {
  return Math.round(Math.random() * (max - min)) + min;
}

document.write(randomNumber(99,100) + "<br />");

2 Answers

Matthew Batman
Matthew Batman
30,187 Points
Matthew Batman
Matthew Batman
30,187 Points

math.ceil and math.floor round in a specific direction (up and down), while math.round will round "accurately." So, math.round could give you a "0" in instances where math.ceil could give you a "1" (ie. if the input was 0.4).

Jose Laverde
Jose Laverde
3,575 Points
Jose Laverde
Jose Laverde
3,575 Points

Good answer. I would just add that you should say "in instances where math.ceil WILL give you a '1'..."

This sounds less ambiguious.

Bryan Peters
Bryan Peters
11,996 Points
Bryan Peters
Bryan Peters
11,996 Points

When used with the random number generator, Math.round will skew your distribution. More info here