freecodecamp--freecodecamp/curriculum/challenges/english/blocks/daily-coding-challenges-python/68b7cadffed0e75a517da675.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
68b7cadffed0e75a517da675	Challenge 53: Decimal to Binary	29	challenge-53

--description--

Given a non-negative integer, return its binary representation as a string.

A binary number uses only the digits 0 and 1 to represent any number. To convert a decimal number to binary, repeatedly divide the number by 2 and record the remainder. Repeat until the number is zero. Read the remainders last recorded to first. For example, to convert 12 to binary:

12 ÷ 2 = 6 remainder 0
6 ÷ 2 = 3 remainder 0
3 ÷ 2 = 1 remainder 1
1 ÷ 2 = 0 remainder 1

12 in binary is 1100.

--hints--

to_binary(5) should return "101".

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(to_binary(5), "101")`)
}})

to_binary(12) should return "1100".

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(to_binary(12), "1100")`)
}})

to_binary(50) should return "110010".

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(to_binary(50), "110010")`)
}})

to_binary(99) should return "1100011".

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(to_binary(99), "1100011")`)
}})

--seed--

--seed-contents--

def to_binary(decimal):

    return decimal

--solutions--

def to_binary(decimal):
    if decimal == 0:
        return "0"
    binary = ""
    while decimal > 0:
        binary = str(decimal % 2) + binary
        decimal //= 2
    return binary