119 lines
2.7 KiB
Markdown
119 lines
2.7 KiB
Markdown
---
|
|
id: 56533eb9ac21ba0edf2244c6
|
|
title: Stand in Line
|
|
challengeType: 1
|
|
videoUrl: 'https://scrimba.com/c/ca8Q8tP'
|
|
---
|
|
|
|
## Description
|
|
<section id='description'>
|
|
In Computer Science a <dfn>queue</dfn> is an abstract <dfn>Data Structure</dfn> where items are kept in order. New items can be added at the back of the queue and old items are taken off from the front of the queue.
|
|
Write a function <code>nextInLine</code> which takes an array (<code>arr</code>) and a number (<code>item</code>) as arguments.
|
|
Add the number to the end of the array, then remove the first element of the array.
|
|
The <code>nextInLine</code> function should then return the element that was removed.
|
|
</section>
|
|
|
|
## Instructions
|
|
<section id='instructions'>
|
|
|
|
</section>
|
|
|
|
## Tests
|
|
<section id='tests'>
|
|
|
|
```yml
|
|
tests:
|
|
- text: <code>nextInLine([], 5)</code> should return a number.
|
|
testString: assert.isNumber(nextInLine([],5));
|
|
- text: <code>nextInLine([], 1)</code> should return <code>1</code>
|
|
testString: assert(nextInLine([],1) === 1);
|
|
- text: <code>nextInLine([2], 1)</code> should return <code>2</code>
|
|
testString: assert(nextInLine([2],1) === 2);
|
|
- text: <code>nextInLine([5,6,7,8,9], 1)</code> should return <code>5</code>
|
|
testString: assert(nextInLine([5,6,7,8,9],1) === 5);
|
|
- text: After <code>nextInLine(testArr, 10)</code>, <code>testArr[4]</code> should be <code>10</code>
|
|
testString: nextInLine(testArr, 10); assert(testArr[4] === 10);
|
|
|
|
```
|
|
|
|
</section>
|
|
|
|
## Challenge Seed
|
|
<section id='challengeSeed'>
|
|
|
|
<div id='js-seed'>
|
|
|
|
```js
|
|
function nextInLine(arr, item) {
|
|
// Your code here
|
|
|
|
return item; // Change this line
|
|
}
|
|
|
|
// Test Setup
|
|
var testArr = [1,2,3,4,5];
|
|
|
|
// Display Code
|
|
console.log("Before: " + JSON.stringify(testArr));
|
|
console.log(nextInLine(testArr, 6)); // Modify this line to test
|
|
console.log("After: " + JSON.stringify(testArr));
|
|
```
|
|
|
|
</div>
|
|
|
|
### Before Test
|
|
<div id='js-setup'>
|
|
|
|
```js
|
|
var logOutput = [];
|
|
var originalConsole = console
|
|
function capture() {
|
|
var nativeLog = console.log;
|
|
console.log = function (message) {
|
|
logOutput.push(message);
|
|
if(nativeLog.apply) {
|
|
nativeLog.apply(originalConsole, arguments);
|
|
} else {
|
|
var nativeMsg = Array.prototype.slice.apply(arguments).join(' ');
|
|
nativeLog(nativeMsg);
|
|
}
|
|
};
|
|
}
|
|
|
|
function uncapture() {
|
|
console.log = originalConsole.log;
|
|
}
|
|
|
|
capture();
|
|
```
|
|
|
|
</div>
|
|
|
|
### After Test
|
|
<div id='js-teardown'>
|
|
|
|
```js
|
|
uncapture();
|
|
testArr = [1,2,3,4,5];
|
|
(function() { return logOutput.join("\n");})();
|
|
```
|
|
|
|
</div>
|
|
|
|
</section>
|
|
|
|
## Solution
|
|
<section id='solution'>
|
|
|
|
|
|
```js
|
|
var testArr = [ 1,2,3,4,5];
|
|
|
|
function nextInLine(arr, item) {
|
|
arr.push(item);
|
|
return arr.shift();
|
|
}
|
|
```
|
|
|
|
</section>
|