Accessors vs. public members

Question

I have a class with a lot of built-in type members with read/write access. Should I make them public members and provide get/set methods for each one? How about structures?

Answer 1

The whole reason to have accessors (getters) and modifiers (setters) is to provide yourself with an extra level of indirection.

This extra level of indirection allows you to provide a read only view of your variable to a public interface, while not allowing your data member to be changed. You could still use a private or protected setter.

Setters allow you to do special error checking, validation and corrections when a value is set. For example setDirectory(const std::string &strPath), you could make sure there is a terminating slash if the user didn't specify one. This ensures that your class state will always be valid.

Getters can also shield your members from having them exposed to allow pointers to them. By not allowing pointers to them from the outside, you can ensure that if your object goes out of scope it won't lead to a crash.

The extra level of indirection for getters/setters also allow you to be able to change the data member that they encapsulate.

With a getter you can also obtain different views of your data, example: getMinutes, when your data member is actually stored in seconds.

This is not the reason to use them, but a nice side effect of using getters and setters is that you can set a breakpoint inside your modifier for example to see exactly when it is changed.

Whether you should use them or not is a judgement call based on your need. If you have so many members that it is a huge pain to provide getters and settings you could consider storing the data members in a struct and using that struct inside your class instead. You could even provide getters/setters for an object for the whole struct at once.

Answer 2

If there are invariants you need to preserve, then yes. Otherwise, don't bother.