"""Convert a Decimal Number to a Binary Number."""


def decimal_to_binary_iterative(num: int) -> str:
 """
 Convert an Integer Decimal Number to a Binary Number as str.
 >>> decimal_to_binary_iterative(0)
 '0b0'
 >>> decimal_to_binary_iterative(2)
 '0b10'
 >>> decimal_to_binary_iterative(7)
 '0b111'
 >>> decimal_to_binary_iterative(35)
 '0b100011'
 >>> # negatives work too
 >>> decimal_to_binary_iterative(-2)
 '-0b10'
 >>> # other floats will error
 >>> decimal_to_binary_iterative(16.16) # doctest: +ELLIPSIS
 Traceback (most recent call last):
 ...
 TypeError: 'float' object cannot be interpreted as an integer
 >>> # strings will error as well
 >>> decimal_to_binary_iterative('0xfffff') # doctest: +ELLIPSIS
 Traceback (most recent call last):
 ...
 TypeError: 'str' object cannot be interpreted as an integer
 """

 if isinstance(num, float):
 raise TypeError("'float' object cannot be interpreted as an integer")
 if isinstance(num, str):
 raise TypeError("'str' object cannot be interpreted as an integer")

 if num == 0:
 return "0b0"

 negative = False

 if num < 0:
 negative = True
 num = -num

 binary: list[int] = []
 while num > 0:
 binary.insert(0, num % 2)
 num >>= 1

 if negative:
 return "-0b" + "".join(str(e) for e in binary)

 return "0b" + "".join(str(e) for e in binary)


def decimal_to_binary_recursive_helper(decimal: int) -> str:
 """
 Take a positive integer value and return its binary equivalent.
 >>> decimal_to_binary_recursive_helper(1000)
 '1111101000'
 >>> decimal_to_binary_recursive_helper("72")
 '1001000'
 >>> decimal_to_binary_recursive_helper("number")
 Traceback (most recent call last):
 ...
 ValueError: invalid literal for int() with base 10: 'number'
 """
 decimal = int(decimal)
 if decimal in (0, 1): # Exit cases for the recursion
 return str(decimal)
 div, mod = divmod(decimal, 2)
 return decimal_to_binary_recursive_helper(div) + str(mod)


def decimal_to_binary_recursive(number: str) -> str:
 """
 Take an integer value and raise ValueError for wrong inputs,
 call the function above and return the output with prefix "0b" & "-0b"
 for positive and negative integers respectively.
 >>> decimal_to_binary_recursive(0)
 '0b0'
 >>> decimal_to_binary_recursive(40)
 '0b101000'
 >>> decimal_to_binary_recursive(-40)
 '-0b101000'
 >>> decimal_to_binary_recursive(40.8)
 Traceback (most recent call last):
 ...
 ValueError: Input value is not an integer
 >>> decimal_to_binary_recursive("forty")
 Traceback (most recent call last):
 ...
 ValueError: Input value is not an integer
 """
 number = str(number).strip()
 if not number:
 raise ValueError("No input value was provided")
 negative = "-" if number.startswith("-") else ""
 number = number.lstrip("-")
 if not number.isnumeric():
 raise ValueError("Input value is not an integer")
 return f"{negative}0b{decimal_to_binary_recursive_helper(int(number))}"


if __name__ == "__main__":
 import doctest

 doctest.testmod()

 print(decimal_to_binary_recursive(input("Input a decimal number: ")))