mirror of
https://github.com/TheAlgorithms/Python.git
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02d9bc66c1
* Added binary shifts and twos complement functions to bit manipulation package * Fixed problem representing 0 wrong * More testing * Fixed problems * Fixed formatting * More format fixes * Format fixes * Fixed docstrings and added url * Minor change to url
44 lines
1.1 KiB
Python
44 lines
1.1 KiB
Python
# Information on 2's complement: https://en.wikipedia.org/wiki/Two%27s_complement
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def twos_complement(number: int) -> str:
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"""
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Take in a negative integer 'number'.
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Return the two's complement representation of 'number'.
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>>> twos_complement(0)
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'0b0'
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>>> twos_complement(-1)
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'0b11'
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>>> twos_complement(-5)
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'0b1011'
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>>> twos_complement(-17)
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'0b101111'
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>>> twos_complement(-207)
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'0b100110001'
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>>> twos_complement(1)
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Traceback (most recent call last):
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...
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ValueError: input must be a negative integer
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"""
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if number > 0:
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raise ValueError("input must be a negative integer")
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binary_number_length = len(bin(number)[3:])
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twos_complement_number = bin(abs(number) - (1 << binary_number_length))[3:]
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twos_complement_number = (
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(
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"1"
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+ "0" * (binary_number_length - len(twos_complement_number))
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+ twos_complement_number
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)
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if number < 0
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else "0"
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)
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return "0b" + twos_complement_number
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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