CSE 222: Software Components in Engineering (SCE) – Introduction

1. CSE 222: Software Components in Engineering (SCE) – Introduction Instructor: Jimmy Voss Disclaimer: Not all material is original. Some is taken from the official course slides, and some is taken from Anna’s slides.

2. Syllabus Information • Course Coordinator: Dr. Bruce Weide • Instructor: Jimmy Voss • E-mail: vossj@cse.ohio-state.edu • Office: 407 Caldwell • Office Hours: 2:30 – 3:30 TuTh • Course website: • http://www.cse.ohio-state.edu/sce/now/222/

3. Overview of Course • Use RESOLVE/C++ to teach programming concepts and software engineering principles: • Use of data structures • Client View and Implementer’s View • Design by contract • Memory management / pointers • Data structure implementations

4. What is RESOLVE/C++? • An approach to programming in C++ • Uses formal comments to specify precise program behavior. • Implemented using macros, classes, and formal comments. • Implements a set of template libraries. • Implements 4 standard operations for all components.

5. Review of Resolve • Combines a programming language (C++) and a specification language. • For code to be correct, it must work precisely when the specifications are met. • Use formal comments for specifications. • Some specifications described via keywords which have no meaning in C++. • Disciplined way of programming C++

6. Review of Resolve • All Resolve components are classes with 4 predefined operations: • Swap-- denoted &= • Constructor • Destructor • Clear member function

7. Sequence -- A Resolve/C++ component • a sequence is an ordered grouping of objects • Example: “abc” is an ordered sequence of characters. A Text object could be used. • Sequence – the Abstract RESOLVE/C++ component: • 4 operations allowed: • Add( pos, x ) • Remove( pos, x ) • Accessor, i.e., [pos] • Length()

8. Instantiating Sequence #include "RESOLVE_Foundation.h" #include "CT/Sequence/Kernel_1a_C.h" concrete_instance class Sequence_Of_Integer : instantiates Sequence_Kernel_1a_C <Integer> {};

9. Instantiating Sequence #include "RESOLVE_Foundation.h" #include "CT/Sequence/Kernel_1a_C.h" concrete_instance class Sequence_Of_Integer : instantiates Sequence_Kernel_1a_C <Integer> {}; Preprocessor directives RESOLVE Keyword Template parameter

10. Preprocessor directives • #include • Used to include the contents of another file at the current location in the current file. • Example: • #include "RESOLVE_Foundation.h" • #define • Used for text replacement which occurs before the program is compiled. • Examples: • #define concrete_instance • #define procedure_body virtual void

11. Template parameters • Template parameter – a token which represents a type name. • Classes and functions can be defined on arbitrary types. To use such classes / functions, the user must supply the template parameter. • Container classes such as Sequence require a template parameter to be instantiated. • In this course, we instantiate template parameters via inheritance.

12. Inheritance and templating • Inheritance takes on the form: class child : instantiates parent • The child class contains all member functions and variables of the parent class. • If the parent class has requires a template parameter, then a new class with the template parameter filled in is created via: parent< template_type > • Note: This is not the only way of filling in template parameters.

13. Instantiating Sequence #include "RESOLVE_Foundation.h" #include "CT/Sequence/Kernel_1a_C.h" concrete_instance class Sequence_Of_Integer : instantiates Sequence_Kernel_1a_C <Integer> {}; Preprocessor directives RESOLVE Keyword Template type parameter

16. Pass by reference Formal Comment / the contract

17. An Example (Continued) global_procedure Smooth( preserves Sequence_Of_Integer & s1, produces Sequence_Of_Integer & s2 ) /*! ... !*/ { // s2 is produces mode and should not depend on // the input. s2.Clear(); object Integer Index = 0; while ( Index < s1.Length() - 1 ) { s2.Add( Index, (s1[Index] + s1[Index+1]) / 2 ); } }

18. Set • Set – A set is an unordered collection of objects which contain no duplicates. • Examples of sets: • {1, 2, 3, 4, 5} • {} • {“Bob”, “the cat”, “Tom”, “Random string”} • Not a set: • {0, 0, 1, 2}

19. Requires: x self Requires: x self