تمرین متدهای سفارشی در کاتلین

                "" printHelloKotlin() {
    println("سلام کاتلین")
}

                fun main() {
  ""
}

fun printHelloKotlin() {
    println("سلام کاتلین")
}

                fun main() {
  printString("سلام کاتلین")  
}

fun printString(inputString: "") {
  println(inputString)
}

                fun main() {
  val result = doubleNumber(5)
  println(result) 
}

fun doubleNumber(number: Int): Int {
  val result = number * 2
  "" result
}

                fun main() {
  val result = doubleNumber(5)
  println(result) 
}

fun doubleNumber(number: Int): Int {
  // result = number * 2
  // return result
  ""
}

                fun isPositive(number: Int): Boolean {
    return if (number > 0) {
        true
    } else {
        false
    }
}

                fun main() {
  val weight = 3
  val destination = "international"
  val result = calculateShippingCost(weight, destination)

  println(result) 
}

fun calculateShippingCost(""): String {
  if (weight <= 0) {
      return "وزن نامعتبر است"
  }

  if (destination == "iran") {
      val shippingCost = 2 * weight
      return shippingCost.toString()
  }

  if (destination == "international") {
      val shippingCost = 6 * weight
      return shippingCost.toString()
  }

  return "مقصد نامعتبر است"
}

                fun main() {
  val weight = 3
  val destination = "international"
  val result = calculateShippingCost(weight, destination)

  println(result) 
}

fun calculateShippingCost(weight: Int, destination: String): String {
  if (weight <= 0) {
      return "وزن نامعتبر است"
  }

  if (destination == "iran") {
      val shippingCost = 2 * weight
      return shippingCost.toString()
  }

  if (destination == "international") {
      val shippingCost = 6 * weight
      return shippingCost.toString()
  }

  return "مقصد نامعتبر است"
}

                fun main() {
  val result = checkNumber(20)
  println(result)
}

fun checkNumber(number: Int): Int {
  if (number > 0) {
      return "عدد مثبت است"
  } else if (number < 0) {
      return "عدد منفی است"
  }
  return "عدد صفر است"  
}

                fun main() {
  val result = checkNumber(0)
  println(result)
}

fun checkNumber(number: Int): String {
  if (number > 0) {
      return "عدد مثبت است"
  } else if (number < 0) {
      return "عدد منفی است"
  }

  return "عدد صفر است"
}

                fun main() {
  val firstName = "Emma"
  val lastName = "Smith"
  val result = generateUsername(firstName, lastName, "_")

  println(result)
}

fun generateUsername(firstName: String, lastName: String, separator: String): String {
  val username = "$firstName$separator$lastName"
  return username
}

                fun main() {
  val firstName = "Emma"
  val lastName = "Smith"
  val result = generateUsername(firstName, lastName, ".")

  println(result)
}

fun generateUsername(firstName: String, lastName: String, separator: String = "_"): String {
  val username = "$firstName$separator$lastName"
  return username
}

                fun main() {
  val firstName = "Emma"
  val lastName = "Smith"
  val result = generateUsername(firstName, lastName)

  println(result)
}

fun generateUsername(firstName: String, lastName: String, separator: String = "_"): String {
  val username = "$firstName$separator$lastName"
  return username
}