75 lines
3.0 KiB
Markdown
75 lines
3.0 KiB
Markdown
---
|
||
id: 56533eb9ac21ba0edf2244de
|
||
title: Adding a Default Option in Switch Statements
|
||
challengeType: 1
|
||
videoUrl: ''
|
||
localeTitle: 在交换机语句中添加默认选项
|
||
---
|
||
|
||
## Description
|
||
<section id="description">在<code>switch</code>语句中，您可能无法将所有可能的值指定为<code>case</code>语句。相反，您可以添加<code>default</code>语句，如果找不到匹配的<code>case</code>语句，将执行该语句。可以把它想象成<code>if/else</code>链中的最后一个<code>else</code>语句。 <code>default</code>语句应该是最后一种情况。 <blockquote> switch（num）{ <br>案例值1： <br>语句1; <br>打破; <br>案例值2： <br>语句2; <br>打破; <br> ... <br>默认： <br> defaultStatement; <br>打破; <br> } </blockquote></section>
|
||
|
||
## Instructions
|
||
<section id="instructions">写一个switch语句来设置以下条件的<code>answer</code> ： <br> <code>"a"</code> - “苹果” <br> <code>"b"</code> - “鸟” <br> <code>"c"</code> - “猫” <br> <code>default</code> - “东西” </section>
|
||
|
||
## Tests
|
||
<section id='tests'>
|
||
|
||
```yml
|
||
tests:
|
||
- text: <code>switchOfStuff("a")</code>的值应为“apple”
|
||
testString: 'assert(switchOfStuff("a") === "apple", "<code>switchOfStuff("a")</code> should have a value of "apple"");'
|
||
- text: <code>switchOfStuff("b")</code>的值应为“bird”
|
||
testString: 'assert(switchOfStuff("b") === "bird", "<code>switchOfStuff("b")</code> should have a value of "bird"");'
|
||
- text: <code>switchOfStuff("c")</code>的值应为“cat”
|
||
testString: 'assert(switchOfStuff("c") === "cat", "<code>switchOfStuff("c")</code> should have a value of "cat"");'
|
||
- text: <code>switchOfStuff("d")</code>的值应为“stuff”
|
||
testString: 'assert(switchOfStuff("d") === "stuff", "<code>switchOfStuff("d")</code> should have a value of "stuff"");'
|
||
- text: <code>switchOfStuff(4)</code>的值应为“stuff”
|
||
testString: 'assert(switchOfStuff(4) === "stuff", "<code>switchOfStuff(4)</code> should have a value of "stuff"");'
|
||
- text: 您不应该使用任何<code>if</code>或<code>else</code>语句
|
||
testString: 'assert(!/else/g.test(code) || !/if/g.test(code), "You should not use any <code>if</code> or <code>else</code> statements");'
|
||
- text: 您应该使用<code>default</code>语句
|
||
testString: 'assert(switchOfStuff("string-to-trigger-default-case") === "stuff", "You should use a <code>default</code> statement");'
|
||
- text: 你应该至少有3个<code>break</code>语句
|
||
testString: 'assert(code.match(/break/g).length > 2, "You should have at least 3 <code>break</code> statements");'
|
||
|
||
```
|
||
|
||
</section>
|
||
|
||
## Challenge Seed
|
||
<section id='challengeSeed'>
|
||
|
||
<div id='js-seed'>
|
||
|
||
```js
|
||
function switchOfStuff(val) {
|
||
var answer = "";
|
||
// Only change code below this line
|
||
|
||
|
||
|
||
// Only change code above this line
|
||
return answer;
|
||
}
|
||
|
||
// Change this value to test
|
||
switchOfStuff(1);
|
||
|
||
```
|
||
|
||
</div>
|
||
|
||
|
||
|
||
</section>
|
||
|
||
## Solution
|
||
<section id='solution'>
|
||
|
||
```js
|
||
// solution required
|
||
```
|
||
</section>
|