freeCodeCamp/curriculum/challenges/en/08-coding-interview-prep/rosetta-code/greatest-common-divisor.en.md

title, id, challengeType

title	id	challengeType
Greatest common divisor	5a23c84252665b21eecc7e82	5

Description

Write a function that returns the greatest common divisor of two integers.

Instructions

Tests

- text: '''<code>gcd</code> should be a function.'''
  testString: 'assert(typeof gcd==''function'',''<code>gcd</code> should be a function.'');'
- text: '''<code>gcd(24,36)</code> should return a number.'''
  testString: 'assert(typeof gcd(24,36)==''number'',''<code>gcd(24,36)</code> should return a number.'');'
- text: '''<code>gcd(24,36)</code> should return <code>12</code>.'''
  testString: 'assert.equal(gcd(24,36),12,''<code>gcd(24,36)</code> should return <code>12</code>.'');'
- text: '''<code>gcd(30,48)</code> should return <code>6</code>.'''
  testString: 'assert.equal(gcd(30,48),6,''<code>gcd(30,48)</code> should return <code>6</code>.'');'
- text: '''<code>gcd(10,15)</code> should return <code>5</code>.'''
  testString: 'assert.equal(gcd(10,15),5,''<code>gcd(10,15)</code> should return <code>5</code>.'');'
- text: '''<code>gcd(100,25)</code> should return <code>25</code>.'''
  testString: 'assert.equal(gcd(100,25),25,''<code>gcd(100,25)</code> should return <code>25</code>.'');'
- text: '''<code>gcd(13,250)</code> should return <code>1</code>.'''
  testString: 'assert.equal(gcd(13,250),1,''<code>gcd(13,250)</code> should return <code>1</code>.'');'
- text: '''<code>gcd(1300,250)</code> should return <code>50</code>.'''
  testString: 'assert.equal(gcd(1300,250),50,''<code>gcd(1300,250)</code> should return <code>50</code>.'');'

Challenge Seed

function gcd(a, b) {
  // Good luck!
}

Solution

function gcd(a, b) {
  return b==0 ? Math.abs(a):gcd(b, a % b);
}