Learning C# 3.0

Test Your Knowledge: Exercises

Exercise 16-1. Create a simple array of three integers. Ask the user which array element she wants to see. Output the integer that the user asked for (remember that the user probably won’t ask for a zero-based index). Provide a way for the user to indicate whether she wants another integer, or to end the program. Provide a handler that deals with invalid input.

Exercise 16-2. Modify the example in Exercise 16-1 to handle two specific errors: the IndexOutOfRangeException, which is used when the user enters a number that’s not valid for the array, and the FormatException, which is used when the entered value doesn’t match the expected format—in this case, if the user enters something that isn’t a number. Leave the existing handler as a default.

Exercise 16-3. Create a Cat class with one int property: Age. Write a program that creates a List of Cat objects in a try block. Create multiple catch statements to handle an ArgumentOutOfRangeException and an unknown exception, and a finally block to simulate deallocating the Cat objects. Write test code to throw an exception that you will catch and handle.

Exercise 16-4. Modify the test code you wrote in Exercise 16-3 so that it does not throw an error. Create a custom error type CustomCatError that derives from System.ApplicationException, and create a handler for it. Add a method to CatManager that checks the cat’s age and throws a new error of type CustomCatError if the age is less than or equal to 0, with an ...