87 lines
2.1 KiB
Markdown
87 lines
2.1 KiB
Markdown
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---
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id: 56533eb9ac21ba0edf2244af
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title: Compound Assignment With Augmented Addition
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challengeType: 1
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---
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## Description
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<section id='description'>
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In programming, it is common to use assignments to modify the contents of a variable. Remember that everything to the right of the equals sign is evaluated first, so we can say:
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<code>myVar = myVar + 5;</code>
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to add <code>5</code> to <code>myVar</code>. Since this is such a common pattern, there are operators which do both a mathematical operation and assignment in one step.
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One such operator is the <code>+=</code> operator.
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<blockquote>var myVar = 1;<br>myVar += 5;<br>console.log(myVar); // Returns 6</blockquote>
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</section>
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## Instructions
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<section id='instructions'>
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Convert the assignments for <code>a</code>, <code>b</code>, and <code>c</code> to use the <code>+=</code> operator.
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</section>
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## Tests
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<section id='tests'>
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```yml
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- text: <code>a</code> should equal <code>15</code>
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testString: 'assert(a === 15, "<code>a</code> should equal <code>15</code>");'
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- text: <code>b</code> should equal <code>26</code>
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testString: 'assert(b === 26, "<code>b</code> should equal <code>26</code>");'
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- text: <code>c</code> should equal <code>19</code>
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testString: 'assert(c === 19, "<code>c</code> should equal <code>19</code>");'
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- text: You should use the <code>+=</code> operator for each variable
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testString: 'assert(code.match(/\+=/g).length === 3, "You should use the <code>+=</code> operator for each variable");'
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- text: Do not modify the code above the line
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testString: 'assert(/var a = 3;/.test(code) && /var b = 17;/.test(code) && /var c = 12;/.test(code), "Do not modify the code above the line");'
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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var a = 3;
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var b = 17;
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var c = 12;
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// Only modify code below this line
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a = a + 12;
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b = 9 + b;
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c = c + 7;
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```
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</div>
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### After Test
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<div id='js-teardown'>
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```js
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console.info('after the test');
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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var a = 3;
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var b = 17;
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var c = 12;
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a += 12;
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b += 9;
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c += 7;
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```
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</section>
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