input: Write a function to convert a given number into its binary format. If the number is 0, return 0. For any other number, return the binary string representation.
  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(1)==1
  assert convert_to_binary(7)==111
  assert convert_to_binary(16)==10000
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