Switch branches/tags
Nothing to show
Find file Copy path
Fetching contributors…
Cannot retrieve contributors at this time
38 lines (28 sloc) 1.15 KB


There are only 10 types of people in the world: those who understand binary, and those who don't. -- Unknown

Converting Decimal to Binary

To convert decimal to binary:

  1. take your decimal number, n
  2. divide your number by 2 and save the dividend and remainder
  3. make the dividend your new number
  4. push the remainder onto a stack
  5. repeat this process until your number is 0
  6. pop all the numbers of the stack to create the binary number

Do this on paper. Stop to understand why the remainder will always be 1 or 0.

FYI: The above technique works with decimal to any base! Just change '2' to the base you want to covert to.

# Returns a binary string
# you would never do this in a real program as Python has `bin(n)`
def decimal2binary(n):
  nba = [] # n as binary array
  div = n # dividend
  while div != 0:
      rem = div % 2
      div = div // 2
  # list comprehension to reverse array and join elements as a string
  return ''.join(str(i) for i in reversed(nba))


Day 10: Binary Numbers. 30 Days of Code. HackerRank.