//
// program to track bank balance
// prompts for initial balance, 
// then 'c' for check, 'd' for deposit, 'q' for quit
//

def nextInput(bal : Int) {
  println("enter c for check, d for deposit, q for quit")
  var which = readChar
  if (which == 'c') {
    println("enter check amount (integer)")
    val check = readInt
    val newBal = bal - check
    println(newBal)
    nextInput(newBal)
  }
  else if (which == 'd') {
    println("enter deposit amount (integer)")
    val deposit = readInt
    val newBal = bal + deposit
    println(newBal)
    nextInput(newBal)
  }
  else if (which == 'q') {
    println("that's all, folks!")
  }
  else {
    println("error!")
    nextInput(bal)
  }
}

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