On the correctness of object classes

The cardinal purpose of teaching programming is to demonstrate a method of developing correct programs. Reliability and correctness are especially important in cases of programs that are intended for multiple reuse. The most characteristic examples of such program-tools are the ones belonging to data types (or data type classes). The method we outline for program development assists in producing correct programs with mathematical formalism. The main point of this method is that we declare statements that refer to the examination of the abstract type class’s operations formulated with algorism. Since there are well-known methods for proving these statements, we do not have to deal with it in this paper. We are going to apply a single example throughout the article. The theorems we need to support our steps are to be declared, but our methods generally do not require elaboration of their proof