Rosetta Code

Four bit adder

Add two four-bit binary values and return the carry with the result bits.

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Sourcerosettacode/popular/four_bit_adder.vibe
type RunResult = {
  fifteen_plus_one: { bits: array<int>, carry: int },
  five_plus_six: { bits: array<int>, carry: int }
}

def add_four_bits(left: array<int>, right: array<int>) -> { bits: array<int>, carry: int }
  carry = 0
  result: array<int> = []
  index = 3

  while index >= 0
    total = left.fetch(index) + right.fetch(index) + carry
    result = [total % 2] + result

    if total >= 2
      carry = 1
    else
      carry = 0
    end

    index = index - 1
  end

  {
    carry: carry,
    bits: result
  }
end

def run -> RunResult
  {
    five_plus_six: add_four_bits([0, 1, 0, 1], [0, 1, 1, 0]),
    fifteen_plus_one: add_four_bits([1, 1, 1, 1], [0, 0, 0, 1])
  }
end

Output

Click Run example to see the result.

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