Basu``s systematic approach to the development of totally correct iteractive programs is classified by manner of generalizations and we investigate those through examples.
We have some abstract data types such as a binary tree and a directed, connected graph. For data domain including these data types, we introduce intra and internal generalization. These manner of extensions are illustrated by the depth first search (DFS) of a graph.
Also this thesis contains a description about the same problems in stack schema.