input: Write a function to convert a number into its binary representation. If the given number is 0, return 0. The function should return the binary representation as a string.
  def convert_to_binary(num):
      if num == 0:
          return '0'
      binary = ''
      while num != 0:
          remainder = num % 2
          binary = str(remainder) + binary
          num = num // 2
      return binary
  
  assert convert_to_binary(10)=='1010'
  assert convert_to_binary(0)=='0'
  assert convert_to_binary(5)=='101'
  assert convert_to_binary(1)=='1'
  assert convert_to_binary(64)=='1000000'
output: def convert_to_binary(num):
      if num == 0:
          return '0'
      binary = ''
      while num != 0:
          remainder = num % 2
          binary = str(remainder) + binary
          num = num // 2
      return binary