There's nothing wrong with "design by contract", but it might bog you down if you're looking at Eiffel just to get more knowledgeable about OO.

Personally, I found that the DbC aspect of Eiffel considerably simplified the process of creating classes. Though I admit I was not an OO beginner when I came to Eiffel.

The reasons are that

• It moves most if not all of the error checking out-of-line of the main method code.

  That means that you can concentrate upon the actual algorithms within the methods, and avoid the clutter of in-line error handling.

• It makes it very easy to specify quite liberal constraints at the outset and then gradually increase these as you more clearly understand what they should (or need) to be.