Question

Define an exception class called tornadoException. The class should have two constructors, including the default constructor. If the exception is thrown with the default constructor, the method what should return "Tornado: Take cover immediately!". The other constructor has a single parameter, say, m, of the int type. If the exception is thrown with this constructor, the method what should return "Tornado: m miles away; and approaching!"

Short answer

Define class `tornadoException` with two constructors and a `what` method returning tornado messages.

Step-by-step solution

Define the Exception Class

Begin by defining a new class called `tornadoException`. This class will be used to represent a specific type of exception in the program related to tornado warnings.

Implement the Default Constructor

Inside the `tornadoException` class, implement a default constructor that initializes the object without any parameters. This constructor will be responsible for setting up default behavior for our exception object.

Implement the Parameterized Constructor

The second constructor in the `tornadoException` class should have a single parameter of type `int`, typically named `m`. This constructor will initialize the exception object with information about the distance of the tornado.

Implement the Method what

Create a method called `what` within the `tornadoException` class that returns a different string based on which constructor was used. If called with the default constructor, it should return "Tornado: Take cover immediately!". If called with the parameterized constructor, it should return a string indicating the distance of the tornado, such as "Tornado: m miles away; and approaching!" where `m` is the value passed to the constructor.

Key concepts

Custom Exception Classes

Creating custom exception classes in C++ can significantly increase the clarity and reliability of your code by allowing you to represent specific error situations. In our example, we are tasked with creating a special exception class named `tornadoException`. This class will help in signaling critical situations regarding tornado warnings within a program.

A custom exception class acts as a template for managing errors specific to the context of the program. By implementing a class like `tornadoException`, you tailor the responses of your program to specific conditions such as "Tornado: Take cover immediately!" or "Tornado: m miles away; and approaching!" where the message provides context-specific information. The deployment of such a class can enhance both the usability and robustness of your software.

Creating these custom exceptions can involve defining constructors and methods that reflect the unique parameters and behavior desired for your exception, as we see in the `tornadoException` class. This added layer of specificity means that errors do not only indicate something went wrong, but also give a detailed description, aiding in debugging and providing immediate insight into the problem at hand.

Constructors in C++

Constructors in C++ are special member functions used for initializing objects. They share the same name as the class and do not have return types. In our example with the `tornadoException` class, we've introduced two constructors: a default constructor and a parameterized constructor.

The default constructor initializes an object without requiring external input. For the `tornadoException` class, the default constructor sets up the object to provide a generic message "Tornado: Take cover immediately!". This makes it straightforward to handle situations when minimal information is available, yet action is required.

On the other hand, a parameterized constructor allows for initializing an object with specific data—in our case, an integer `m` representing miles. This constructor is important for carrying additional data which could determine how the exception should be handled. It broadens the context by, for example, returning "Tornado: m miles away; and approaching!", enabling a more tailored response depending on the severity or proximity of a tornado.

• A constructor does not have a return value.
• Multiple constructors can be defined to handle different initialization scenarios (overloading).
• Initialization lists can be used within constructors to efficiently set object values.

Error Handling Techniques

Error handling is a fundamental aspect of any robust C++ program. Effective error handling ensures the program can deal with unexpected situations gracefully, without causing crashes or undefined behavior. In the context of our `tornadoException` example, having a clear and structured way to manage such situations is crucial.

One common technique in C++ is utilizing try-catch blocks. This allows you to execute code that might potentially throw an exception, and then "catch" this exception to execute an alternative block of code. For instance, when a tornado is detected, the program might throw a `tornadoException`, which could then be caught by a catch block that handles the necessary safety procedures like notifying users or initializing shutdown protocols.

• Use try to wrap the segment of code where you anticipate an exception may arise.
• The catch block is where the program specifies how to manage an exception.
• Derived exception classes can be caught and handled separately from base class exceptions, offering fine-grained control.

Employing appropriate error handling techniques not only protects the integrity of the program but also enhances user experience by ensuring they receive meaningful feedback and instructions.