Question

I have a method DoCleanUp(), which will ask user to proceed and then clear current workspace. It will return if user choose to cancel this process.

My question is, which signature is best to indicate a “cancel”?

1. bool DoCleanUp(); // return false to indicate canceled.

2. bool DoCleanUp(); // return true to indicate this method should be canceled.

3. void DoCleanUp(bool& cancel); // check parameter 'cancel' to see if this method was canceled.

UPDATE: As for the language, it’s C++\CLI or C#.

UPDATE2: Now suppose I have to save a file in the DoCleanUp method. I’ll prompt a dialog ask user whether to save/not save/cancel the file. Based on the answers, here is what I came up:

void DoCleanUp();

DialogResult AskToSaveFile(); // return yes/no/cancel

void DoCleanUp( bool saveFile );

Usage:

void DoCleanUp()
{
    DialogResult result =  AskToSaveFile();

    if( result == DialogResult::Cancel )    return; 

    bool saveFile = (result == DialogResult::Yes) ? true : false;
    DoCleanUp( saveFile );
}

Then by calling DoCleanUp(), you know user will have the opportunity to cancel;
By calling DoCleanUp(bool saveFile), you can control whether to save file without asking user.
Is that looks better?

Answer 1

This is a classic single responsibility problem.

The reason that you are unsure about the signature is that the method is doing 2 things.

I would create 2 methods:

bool CheckIfTheUserWantsToCancel()
void DoCleanUp()

EDIT

Based on the comments and edits to the question I would create a 3rd method:

void SaveFile()

The DoCleanUp would then first call CheckIfTheUserWantsToCancel, and then if not cancelled would call SaveFile.

IMHO this is much better than trying to remember that DoCleanUp with parameter false will save the file without asking the user, or was it the other way around?