2018-10-10 22:03:03 +00:00
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---
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id: cf1111c1c12feddfaeb2bdef
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2021-03-04 17:49:46 +00:00
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title: 生成某个范围内的随机整数
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2018-10-10 22:03:03 +00:00
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challengeType: 1
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2020-04-29 10:29:13 +00:00
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videoUrl: 'https://scrimba.com/c/cm83yu6'
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forumTopicId: 18187
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2021-01-13 02:31:00 +00:00
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dashedName: generate-random-whole-numbers-within-a-range
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2018-10-10 22:03:03 +00:00
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---
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2020-12-16 07:37:30 +00:00
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# --description--
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2018-10-10 22:03:03 +00:00
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2021-03-04 17:49:46 +00:00
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我们之前生成的随机数是在 0 到某个数之间,现在我们要生成的随机数是在两个指定的数之间。
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2018-10-10 22:03:03 +00:00
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2021-03-04 17:49:46 +00:00
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我们需要定义一个最小值 `min` 和一个最大值 `max`。
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2018-10-10 22:03:03 +00:00
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2021-03-04 17:49:46 +00:00
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下面是我们将要使用的方法, 仔细看看并尝试理解这行代码到底在干嘛:
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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`Math.floor(Math.random() * (max - min + 1)) + min`
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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# --instructions--
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2018-10-10 22:03:03 +00:00
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2021-03-04 17:49:46 +00:00
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创建一个函数 `randomRange`,接收参数的范围在 `myMin` 和 `myMax`之间,返回一个在 `myMin`(包括 myMin)和 `myMax`(包括 myMax)之间的随机整数。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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# --hints--
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2018-10-10 22:03:03 +00:00
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2021-03-04 17:49:46 +00:00
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`randomRange` 返回的随机数应该大于或等于 `myMin`。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert(calcMin === 5);
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2018-10-10 22:03:03 +00:00
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```
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2021-03-04 17:49:46 +00:00
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`randomRange` 返回的随机数最大值应该等于 `myMax`。
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2018-10-10 22:03:03 +00:00
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```js
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2020-12-16 07:37:30 +00:00
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assert(calcMax === 15);
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2018-10-10 22:03:03 +00:00
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```
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2021-03-04 17:49:46 +00:00
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`randomRange` 应该返回一个随机整数,而不是小数。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert(randomRange(0, 1) % 1 === 0);
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```
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2018-10-10 22:03:03 +00:00
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2021-03-04 17:49:46 +00:00
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`randomRange` 应该使用 `myMax` 和 `myMin`,并且返回两者之间的随机数。
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2020-04-29 10:29:13 +00:00
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2018-10-10 22:03:03 +00:00
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```js
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2020-12-16 07:37:30 +00:00
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assert(
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(function () {
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if (
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code.match(/myMax/g).length > 1 &&
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code.match(/myMin/g).length > 2 &&
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code.match(/Math.floor/g) &&
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code.match(/Math.random/g)
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) {
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return true;
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} else {
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return false;
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}
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})()
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);
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2018-10-10 22:03:03 +00:00
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```
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2020-04-29 10:29:13 +00:00
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2021-01-13 02:31:00 +00:00
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# --seed--
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## --after-user-code--
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```js
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var calcMin = 100;
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var calcMax = -100;
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for(var i = 0; i < 100; i++) {
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var result = randomRange(5,15);
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calcMin = Math.min(calcMin, result);
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calcMax = Math.max(calcMax, result);
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}
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(function(){
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if(typeof myRandom === 'number') {
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return "myRandom = " + myRandom;
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} else {
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return "myRandom undefined";
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}
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})()
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```
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## --seed-contents--
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```js
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function randomRange(myMin, myMax) {
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// Only change code below this line
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return 0;
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// Only change code above this line
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}
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```
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2020-12-16 07:37:30 +00:00
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# --solutions--
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2021-01-13 02:31:00 +00:00
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```js
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function randomRange(myMin, myMax) {
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return Math.floor(Math.random() * (myMax - myMin + 1)) + myMin;
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}
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```
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