I’m starting to write some code using C++ and I have this simple class method from a simple task manager program I’m writing as an experiment:
void Task::setText(string text)
{
if(text.length() > MIN_LENGTH)
{
this->text = text;
}
}
As you can see, this method sets the class text attribute to the one passed to the method if it’s length is higher than the MIN_LENGHT variable that is defined above the code I’ve shown. So I have to do something if the condition does not evaluate to true for the string passed to the method.
In the C++ book I bought, error handlings are not explained, instead it just uses assert everywhere. As assert just aborts the program if the expression is false, and this is intended as input validation, I looked for a better approach.
This search led me to C++ exceptions. There it explains how to create exceptions by creating a class that inherits from exception.
Good OOP practice says that every class should be independent from the others in the program. So where should I put this exception class I create? In the same header I define my Task class in? Or should it be in task.cpp where I define every method of the class?
Maybe this is a silly question but just want to be secure and follow a good software architecture practices from the beginning.
Recommendation #1: You need to read your book completely.
It is not true that in case of every error you should throw an exception. Exception should happen something less often that every 1000 calls to your function/method. 1000 is not a magic value here, in particular case other number might be appropriate.
In other words. The first question that you need to answer: how often this error may happen. If this may happen often, then the return value (bool or enum or int) is a better approach.
If you decided to use exception, it is better to derive it from
std::exception. You should place exceptions of your project in a separate file. Think about a couple of classes, maybe 3-10. It is better to place a data field inside your exception class that should explain details of what happened instead of creating hundreds of different exception classes.