//
// program to track bank balance
// prompts for initial balance, 
// then 'c' for check, 'd' for deposit, 'q' for quit
//
// (this version uses match rather than if/else)
//

def nextInput(bal : Int) {
  println("current balance $" + bal)
  println("enter c for check, d for deposit, q for quit")
  var which = readChar
  which match {
    case 'c' => {
      println("enter check amount (integer)")
      val check = readInt
      nextInput(bal - check)
    }
    case 'd' => {
      println("enter deposit amount (integer)")
      val deposit = readInt
      nextInput(bal + deposit)
    }
    case 'q' => {
      println("that's all, folks!")
    }
    case _ => {
      println("error!")
      nextInput(bal)
    }
  }
}

println("starting balance (integer):")
val balance = readInt
nextInput(balance)