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Object-oriented Programming in C#
Contracts and Assertions
* Correctness
Software Qualities
Correctness
Specifications
* Specification with preconditions and postconditions
Logical expressions
Examples of preconditions and postconditions
An Assertion Language
* Responsibilities and Contracts
Questions Related to Responsibility
Division of Responsibilities
The highly responsible program
Responsibility division by pre and postconditions
Contracts
Everyday Contracts
Contracts: Obligations and Benefits
Obligations and Benefits in Sqrt
* Class Invariants
General aspects of contracts
Everyday invariants
An example of a class invariant
* Inheritance is Subcontracting
Inheritance and Contracts
Subcontracting
Class invariants in the triangle class hierarchy
Assertions in Abstract classes
* Design by Contract
Design by Contract
DBC and Programming Languages
Code Contracts in C# 4.0
* Loop Invariants
Loop Invariants
Correctness
A correct program -
in relation to what?
The programmers own, immediate comprehension
Not formulated - not documented - volatile - easily forgotten
Sometimes incomplete
A program specification
Formulated - written
Well-considered and agreed upon
Formal or informal
Part of the program
