input: Write a function to convert a given number into binary format. If the input 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(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