decimal_to_binary.py

"""
Author :- mehul-sweeti-agrawal

Task :- Given a positive decimal integer, convert it to binary

    Input  - 9
    Output - 1001

"""


def convert_to_binary(number: int) -> int:
    """
    Returns binary equivalent of a decimal number
    >>> convert_to_binary(8)
    1000
    >>> convert_to_binary(5)
    101
    >>> convert_to_binary(-3)
    Traceback (most recent call last):
      ...
    ValueError: number must be non-negative
    >>> convert_to_binary(9.8)
    Traceback (most recent call last):
      ...
    TypeError: unsupported operand type(s) for &: 'float' and 'int'
    """

    # For negative numbers
    if number < 0:
        raise ValueError("number must be non-negative")

    power = 1  # helper variable
    ans = 0  # stores binary equivalent of decimal number
    while number:
        if number & 1:
            ans += power
        power *= 10
        number >>= 1
    return ans


if __name__ == "__main__":
    import doctest

    doctest.testmod()