freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/generate-random-whole-numbers-with-javascript.md

id, title, challengeType, videoUrl, forumTopicId, dashedName

id	title	challengeType	videoUrl	forumTopicId	dashedName
cf1111c1c12feddfaeb1bdef	Generate Random Whole Numbers with JavaScript	1	https://scrimba.com/c/cRn6bfr	18186	generate-random-whole-numbers-with-javascript

--description--

You can generate random decimal numbers with Math.random(), but sometimes you need to generate random whole numbers. The following process will give you a random whole number less than 20:

1. Use Math.random() to generate a random decimal number.
2. Multiply that random decimal number by 20.
3. Use Math.floor() to round this number down to its nearest whole number.

Remember that Math.random() can never quite return a 1, so it's impossible to actually get 20 since you are rounding down with Math.floor(). This process will give you a random whole number in the range from 0 to 19.

Putting everything together, this is what your code looks like:

Math.floor(Math.random() * 20);

You are calling Math.random(), multiplying the result by 20, then passing the value to Math.floor() to round the value down to the nearest whole number.

--instructions--

Use this technique to generate and return a random whole number in the range from 0 to 9.

--hints--

The result of randomWholeNum should be a whole number.

assert(
  typeof randomWholeNum() === 'number' &&
    (function () {
      var r = randomWholeNum();
      return Math.floor(r) === r;
    })()
);

You should use Math.random to generate a random number.

assert(code.match(/Math.random/g).length >= 1);

You should have multiplied the result of Math.random by 10 to make it a number in the range from zero to nine.

assert(
  code.match(/\s*?Math.random\s*?\(\s*?\)\s*?\*\s*?10[\D]\s*?/g) ||
    code.match(/\s*?10\s*?\*\s*?Math.random\s*?\(\s*?\)\s*?/g)
);

You should use Math.floor to remove the decimal part of the number.

assert(code.match(/Math.floor/g).length >= 1);

--seed--

--after-user-code--

(function(){return randomWholeNum();})();

--seed-contents--

function randomWholeNum() {
  return Math.random();
}

--solutions--

function randomWholeNum() {
  return Math.floor(Math.random() * 10);
}