mirror of
https://github.com/freeCodeCamp/freeCodeCamp.git
synced 2025-12-31 06:01:50 -05:00
90 lines
2.2 KiB
Markdown
90 lines
2.2 KiB
Markdown
---
|
|
id: cf1111c1c12feddfaeb1bdef
|
|
title: Zufällige Ganzzahlen mit JavaScript generieren
|
|
challengeType: 1
|
|
videoUrl: 'https://scrimba.com/c/cRn6bfr'
|
|
forumTopicId: 18186
|
|
dashedName: 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:
|
|
|
|
```js
|
|
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--
|
|
|
|
Das Ergebnis von `randomWholeNum` sollte eine ganze Zahl sein.
|
|
|
|
```js
|
|
assert(
|
|
typeof randomWholeNum() === 'number' &&
|
|
(function () {
|
|
var r = randomWholeNum();
|
|
return Math.floor(r) === r;
|
|
})()
|
|
);
|
|
```
|
|
|
|
Du solltest `Math.random` verwenden, um eine Zufallszahl zu erzeugen.
|
|
|
|
```js
|
|
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.
|
|
|
|
```js
|
|
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)
|
|
);
|
|
```
|
|
|
|
Du solltest `Math.floor` verwenden, um den Dezimalteil der Zahl zu entfernen.
|
|
|
|
```js
|
|
assert(code.match(/Math.floor/g).length >= 1);
|
|
```
|
|
|
|
# --seed--
|
|
|
|
## --after-user-code--
|
|
|
|
```js
|
|
(function(){return randomWholeNum();})();
|
|
```
|
|
|
|
## --seed-contents--
|
|
|
|
```js
|
|
function randomWholeNum() {
|
|
return Math.random();
|
|
}
|
|
```
|
|
|
|
# --solutions--
|
|
|
|
```js
|
|
function randomWholeNum() {
|
|
return Math.floor(Math.random() * 10);
|
|
}
|
|
```
|