Question

How to handle invalid argument in Scala

Answer 1

def checkNumber(num: Int): Unit = {
  if (num < 0) throw new IllegalArgumentException("Negative numbers are not allowed")
  println(s"number: $num")
}

try {
  checkNumber(-8) // Throws IllegalArgumentException
} catch {
  case e: IllegalArgumentException => println(s"Error: ${e.getMessage}")
}


 
/*
run:

Error: Negative numbers are not allowed

*/

 

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Answer 2

def isValidInput(num: Int): Boolean = num >= 0

val num = -8
if (isValidInput(num)) println(s"Valid input: $num")
else println("Invalid input detected - Number must be positive")



 
/*
run:

Invalid input detected - Number must be positive

*/

 

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Answer 3

def safeProcessNumber(num: Int): Option[Int] =
  if (num < 0) None else Some(num * 2)

safeProcessNumber(-1) match {
  case Some(value) => println(s"Result: $value")
  case None        => println("Invalid argument detected - Number must be positive")
}


 
/*
run:

Invalid argument detected - Number must be positive

*/

 

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Answer 4

def safeDivide(a: Int, b: Int): Either[String, Int] =
  if (b == 0) Left("Division by zero is not allowed") else Right(a / b)

safeDivide(4, 0) match {
  case Right(result) => println(s"Result: $result")
  case Left(error)   => println(s"Error: $error")
}


 
/*
run:

Error: Division by zero is not allowed

*/

 

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