Checking for valid entries

[abond]

Setting a User Input to a Double (Or a Specific Data Type)

Try this instead which checks that what you’re entering is a valid number and, if it isn’t, asks you to reinput it: var originalTotal: Double? do { print("Enter the original total : ") originalTotal = readLine()!!.toDoubleOrNull() if (originalTotal == null) println("Not a valid number, try again") } while (originalTotal == null) var tip = 0.15 * originalTotal println("Your tip is : $tip") var total = originalTotal + tip println("Your total…