scala 标识符案例

package com.youlangta.scalaTest

class Rational(n: Int, d: Int) {
  require(d != 0, "分母不能为0")
  private val g = gcd(n.abs, d.abs)
  val number: Int = n / g
  val denom: Int = d / g

  override def toString: String = number + "/" + denom

  def this(n: Int) = this(n, 1)

  def +(that: Rational): Rational = {
    new Rational(
      number * that.denom + that.number * denom,
      denom * that.denom
    )
  }

  def +(i: Int): Rational = {
    new Rational(
      number + i * denom, denom
    )
  }


  def -(that: Rational): Rational = {
    new Rational(
      number * that.denom - that.number * denom,
      denom * that.denom
    )
  }

  def -(i: Int): Rational = {
    new Rational(
      number - i * denom, denom
    )
  }

  def *(that: Rational): Rational = {
    new Rational(
      number * that.number,
      denom * that.denom
    )
  }

  def *(i: Int): Rational = {
    new Rational(
      number * i, denom
    )
  }

  def /(that: Rational): Rational = {
    new Rational(
      number * that.denom,
      denom * that.number
    )
  }

  def /(i: Int): Rational = {
    new Rational(
      number, denom * i
    )
  }

  private def gcd(a: Int, b: Int): Int = {
    if (b == 0) a else gcd(b, a % b)
  }
}