A colleague of mine states that booleans as method arguments are not acceptable. They shall be replaced by enumerations. At first I did not see any benefit, but he gave me an example.

What's easier to understand?

file.writeData( data, true );

Or

enum WriteMode {
  Append,
  Overwrite
};

file.writeData( data, Append );

Now I got it! ;-)
This is definitely an example where an enumeration as second parameter makes the code much more readable.

So, what's your opinion on this topic?