---
id: 5a23c84252665b21eecc8042
title: Sum of squares
challengeType: 5
---

## Description
<section id='description'>
Write a function to find the sum of squares of an array of integers.
</section>

## Instructions
<section id='instructions'>

</section>

## Tests
<section id='tests'>

``` yml
tests:
  - text: <code>sumsq</code> should be a function.
    testString: assert(typeof sumsq == 'function', '<code>sumsq</code> should be a function.');
  - text: <code>sumsq([1, 2, 3, 4, 5])</code> should return a number.
    testString: assert(typeof sumsq([1, 2, 3, 4, 5]) == 'number', '<code>sumsq([1, 2, 3, 4, 5])</code> should return a number.');
  - text: <code>sumsq([1, 2, 3, 4, 5])</code> should return <code>55</code>.
    testString: assert.equal(sumsq([1, 2, 3, 4, 5]), 55, '<code>sumsq([1, 2, 3, 4, 5])</code> should return <code>55</code>.');
  - text: <code>sumsq([25, 32, 12, 7, 20])</code> should return <code>2242</code>.
    testString: assert.equal(sumsq([25, 32, 12, 7, 20]), 2242, '<code>sumsq([25, 32, 12, 7, 20])</code> should return <code>2242</code>.');
  - text: <code>sumsq([38, 45, 35, 8, 13])</code> should return <code>4927</code>.
    testString: assert.equal(sumsq([38, 45, 35, 8, 13]), 4927, '<code>sumsq([38, 45, 35, 8, 13])</code> should return <code>4927</code>.');
  - text: <code>sumsq([43, 36, 20, 34, 24])</code> should return <code>5277</code>.
    testString: assert.equal(sumsq([43, 36, 20, 34, 24]), 5277, '<code>sumsq([43, 36, 20, 34, 24])</code> should return <code>5277</code>.');
  - text: <code>sumsq([12, 33, 26, 18, 1, 16, 3])</code> should return <code>2499</code>.
    testString: assert.equal(sumsq([12, 33, 26, 18, 1, 16, 3]), 2499, '<code>sumsq([12, 33, 26, 18, 1, 16, 3])</code> should return <code>2499</code>.');
```

</section>

## Challenge Seed
<section id='challengeSeed'>
<div id='js-seed'>

```js
function sumsq (array) {
  // Good luck!
}
```

</div>
</section>

## Solution
<section id='solution'>

```js
function sumsq (array) {
  var sum = 0;
  var i, iLen;

  for (i = 0, iLen = array.length; i < iLen; i++) {
    sum += array[i] * array[i];
  }
  return sum;
}
```

</section>