The content of this repository

- problems
    textual descriptions of the challenge problems, 
    together with their implementation in Eiffel (only requirement specifications, no invariant protocol/framing)
- sc
    solutions to challenge problems using the semantic collaboration methodology
- sc_no_defaults
    solutions to challenge problems using semantic collaboration without default annotations
Challenge Problems

In roughly increasing order of complexity:
- Observer
- Iterator
- Master Clock
- Doubly-Linked List
- Composite