全加算器と半加算器を使った加算器の実装

Adder.scala

/**
 * Adder of two numbers
 */
object Adder {

  val BINARY_REGEX  = "(^[01]+$)".r
  val DECIMAL_REGEX = "(^[0-9]+$)".r

  /**
   * Arguments must be decimal numbers or binary numbers
   * ***************************************************
   * Usage:
   * `runMain calculator.Adder 3 5`
   * `runMain calculator.Adder 11 101`
   * ***************************************************
   */
  def main(args: Array[String]): Unit =
    args.length == 2 match {
      case true  => {
        val num1 = args(0)
        val num2 = args(1)
        println(s"$num1 + $num2 = ???")
        (num1, num2) match {
          case (BINARY_REGEX(b1),   BINARY_REGEX(b2)) => {
            val result = addBinary(b1, b2)
            println(s"result: $result")
          }
          case (DECIMAL_REGEX(d1), DECIMAL_REGEX(d2)) => {
            val result = add(d1.toInt, d2.toInt)
            println(s"result: $result")
          }
          case _ => throw new IllegalArgumentException
        }
      }
      case false =>
        throw new IllegalArgumentException
    }

  /**
   * Calculate sum of two decimal numbers
   */
  def add(num1: Int, num2: Int): Int =
    Integer.parseInt(
      addBinary(num1.toBinaryString, num2.toBinaryString), 2
    )

  /**
   * Calculate sum of two binary numbers
   */
  def addBinary(bin1: String, bin2: String): String = {
    println(s"binary addition: ${bin1} + ${bin2} = ???")
    val length  = bin1.length.max(bin2.length)
    val revBin1 = bin1.reverse
    val revBin2 = bin2.reverse
    (0 to length).foldLeft(("", 0)) {
      (acc, index) => {
        val bit1     = scala.util.Try(revBin1(index).toInt - '0').getOrElse(0)
        val bit2     = scala.util.Try(revBin2(index).toInt - '0').getOrElse(0)
        val bitSum   = FullAdderBinary.sum    (bit1, bit2, acc._2)
        val bitCarry = FullAdderBinary.carry(bit1, bit2, acc._2)
        println(s"bit: $index) input: num1: $bit1, num2: $bit2, carry: ${acc._2} | output: sum: $bitSum, carry: $bitCarry")
        (bitSum.toString + acc._1, bitCarry)
      }
    }._1
  }
}

FullAdder.scala

/**
 * Binary full adder
 */
object FullAdderBinary {

  /**
   * Calculate sum
   */
  def sum(num1: Int, num2: Int, carry: Int): Int =
    HalfAdderBinary.sum(
      HalfAdderBinary.sum(num1, num2),
      carry
    )

  /**
   * Calculate carry
   */
  def carry(num1: Int, num2: Int, carry: Int): Int =
    HalfAdderBinary.carry(num1, num2) |
      HalfAdderBinary.sum(num1, num2) & carry
}

HalfAdder.scala

/**
 * Binary half adder
 */
object HalfAdderBinary {

  /**
   * Calculate sum
   */
  def sum(num1: Int, num2: Int): Int =
    num1 ^ num2

  /**
   * Calculate carry
   */
  def carry(num1: Int, num2: Int): Int =
    num1 & num2
}