Object Oriented Programming using C++ - Part 1
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The document discusses the transition from procedural programming in C to object-oriented programming in C++, highlighting the evolution, key concepts, and benefits of C++. Key features include classes, inheritance, polymorphism, and encapsulation, which improve code reusability and maintenance. It contrasts procedural and object-oriented approaches through real-world scenarios demonstrating the advantages of the OOP model.
Object Oriented Programming using C++ - Part 1
- 1. OOPS THROUGH C++ Dr. Chandra Sekhar Sanaboina Assistant Professor Department of Computer Science and Engineering University College of Engineering Kakinada Jawaharlal Nehru Technological University Kakinada Website: https://drcs.info Youtube Link: https://www.youtube.com/watch?v=nPjHraTbPeY&list=PLT1ngltOnlJiHbzVvjkU8VzQt9oam8ji4
- 2. UNIT – I INTRODUCTION TO C++
- 3. AGENDA • Difference between C and C++ • Evolution of C++ • Procedure Oriented Programming vs Object Oriented Programming • Key concepts of Object Oriented Programming • Advantages and Disadvantages of OOP 3
- 4. PROCEDURE ORIENTED PROGRAMMING • It means “a set of procedures” which is a “set of subroutines” or a “set of functions“ • Functions are called repeatedly in a program to execute tasks performed by them • Example: A program may involve collecting data from user (reading), performing some kind of calculations on the collected data (calculation), and finally displaying the result to the user when requested (printing). All the 3 tasks of reading, calculating and printing can be written in a program with the help of 3 different functions which performs these 3 different tasks. 4
- 5. A REAL WORLD EXAMPLE • We are working for a vehicle parts manufacturer that needs to update it's online inventory system. Boss tells us to program two similar but separate forms for a website, one form that processes information about cars and one that does the same for trucks • For cars, we will need to record the following information: • Color, Engine Size, Transmission Type, Number of doors • For trucks, the information will be similar, but slightly different. We need: • Color, Engine Size, Transmission Type, Cab Size, Towing Capacity 5
- 6. SCENARIO - 1 • Suppose that we suddenly need to add a bus form, that records the following information: • Color, Engine Size, Transmission Type, Number of passengers • Procedural – • We need to recreate the entire form, repeating the code for Color, Engine Size, and Transmission Type. • OOP - • We simply extend the vehicle class with a bus class and add the method numberOfPassengers 6
- 7. SCENARIO - 2 • Instead of storing color in a database like we previously did, for some strange reason our client wants the color emailed to him • Procedural – • We change three different forms: cars, trucks, and buses to email the color to the client rather than storing it in the database. • OOP – • We change the color method in the vehicle class and because the car, truck, and bus classes all extend (or inherit from, to put it another way) the vehicle class, they are automatically updated 7
- 8. SCENARIO - 3 • We want to move from a generic car to specific makes, for example: Nissan and Creta • Procedural – • We create a new form for each make, repeating all of the code for generic car information and adding the code specific to each make • OOP – • We extend the car class with a Nissan class and a Creta class and add methods for each set of unique information for that car make 8
- 9. SCENARIO - 4 • We found a bug in the transmission type area of our form and need to fix it • Procedural – • We open and update each and every form • OOP – • We fix the transmission Type method in the vehicle class and the change perpetuates in every class that inherits from it 9
- 10. WHY SWITCH TO C++ • Supports an OO approach to programming • Classes • Inheritance • Polymorphism • Exceptions • Provides powerful features on top of a “fast” language 10
- 11. HOW TO SWITCH TO C++ 1. Learn about differences a. New tools (compilers, debuggers, etc.) b. New libraries c. New file naming conventions d. New syntax e. Available standards 2. Rethink programming approach 11
- 12. 1A. NEW TOOLS FOR C++ • Compiler: g++ or CC (CC is only on the SGIs) • Debugger: gdb, dbx (SGI), cvd (SGI), or printf(). ;-) • Some text editors “understand” C++. (formatting, syntax highlighting) 12
- 13. 1B. NEW LIBRARIES FOR C++ • All of the C libraries still work • Some C++ specific libraries 13
- 14. 1C. NEW FILE NAMING CONVENTIONS FOR C++ • Some conventions for file names • foo.h, foo.c – file names under C • foo.hh, foo.cc – file names under C++ • Also foo.cpp, foo.cxx – file names under C++ 14
- 15. 1D. NEW SYNTAX • Syntax virtually identical to C • C++’s features add syntax 15
- 16. 1E. AVAILABLE STANDARDS • ISO/IEC 14882 in 1997 • Adopted ANSI in 1998 16
- 17. SOME QUESTIONS ABOUT C • What is C? • C is a low-level, procedural, systems programming language • What problem did C solve? • Designed as a system’s programming language for UNIX in the 1970s • A fast, flexible, low-level language was needed. 17
- 18. SOME QUESTIONS ABOUT C++ • What is C++? • C++ is an extension of C that provides support for object-oriented programming • What problem did it solve? • Stroustrup states, “I built C++ as a bridge over which people would pass from traditional programming to styles relying on data abstraction and object-oriented programming.” 18
- 19. C VS C++
- 20. C VS C++ C C++ C is a Procedure Oriented Programming Language C++ is an Object Oriented Programming Language Top-Down Approach Bottom-Up Approach C is less secure than C++ C++ is secure (Data Hiding) C programming variable declaration is possible only at top of the program In C++, variable declaration can be done anywhere in the program In C, Namespace feature is not available In C++, Namespace feature is available C is a middle level language C++ is a high level language In C, programs are divided into modules and Functions In C++, programs are divided into classes and Functions Exception Handling not supported Supports Exception Handling 20
- 21. C VS C++ C C++ C Input and Output: scanf(), printf() C++ Input and Output: Cin (>>), cout (<<) In C, main() function can be called through other functions In C++, main() function cannot be called through other functions malloc(), calloc() functions are used for dynamic memory allocation new, delete operators are used for allocating and deallocating memory 21
- 22. EVOLUTION OF C++
- 23. EVOLUTION OF C++ • It has a history going back to 1979 • Bjarne Stroustrup – Developed the C++ • He started work for his Ph.D. thesis • He began work on "C with Classes", which as the name implies was meant to be a superset of the C language • His goal was to add object-oriented programming into the C language which was and still is a language well-respected for its portability without sacrificing speed or low-level functionality • It included classes, basic inheritance, inlining, default function arguments, and strong type checking in addition to all the features of the C language 23
- 24. EVOLUTION OF C++ CONTD… • In 1983 – • the name of the language was changed from “C with Classes” to C++ • The ++ operator in the C language is an operator for incrementing a variable, which gives some insight into how Stroustrup regarded the language • Many new features were added around this time, the most notable of which are virtual functions, function overloading, references with the & symbol, the const keyword, and single-line comments using two forward slashes • In 1985 – • C++ was implemented as a commercial product • The language was not officially standardized yet • In 1989 – • The language was to include protected and static members, as well as an inheritance from several classes. 24
- 25. EVOLUTION OF C++ CONTD… • In 1990 – • Turbo C++ was released as a commercial product • Turbo C++ added a lot of additional libraries which have had a considerable impact on C++'s development. • In 1998 – • the C++ standards committee published the first international standard for C++ ISO/IEC 14882:1998, which is informally known as C++98. The Standard Template Library, which began its conceptual development in 1979, was also included. • In 2003 – • the committee responded to multiple problems that were reported with their 1998 standard and revised it accordingly. The changed language was named C++03. • In mid-2011 – • the new C++ standard (C++11) was finished • The new features included Regex support, a randomization library, a new C++ time library, atomics support, a standard threading library, a new for loop syntax providing functionality similar to for each loops in certain other languages, the auto keyword, new container classes, better support for unions and array-initialization lists and templates. 25
- 26. PROCEDURE ORIENTED PROGRAMMING VS OBJECT ORIENTED PROGRAMMING
- 27. PROCEDURAL ORIENTED PROGRAMMING VS OBJECT ORIENTED PROGRAMMING Procedure Oriented Programming Object Oriented Programming In procedural programming, program is divided into small parts called functions. In object oriented programming, program is divided into small parts called objects. Procedural programming follows top down approach. Object oriented programming follows bottom up approach. There is no access specifier in procedural programming. Object oriented programming have access specifiers like private, public, protected etc. Adding new data and function is not easy. Adding new data and function is easy. Procedural programming does not have any proper way for hiding data so it is less secure. Object oriented programming provides data hiding so it is more secure. In procedural programming, overloading is not possible. Overloading is possible in object oriented programming. In procedural programming, function is more important than data. In object oriented programming, data is more important than function. Procedural programming is based on unreal world. Object oriented programming is based on real world. Examples: C, FORTRAN, Pascal, Basic etc. Examples: C++, Java, Python, C# etc. 27
- 28. KEY CONCEPTS OF OBJECT ORIENTED PROGRAMMING
- 29. KEY CONCEPTS OF OOP Major principles of Object Oriented Programming system are • Class • Object • Inheritance • Polymorphism • Data Abstraction • Encapsulation 29
- 30. CLASS • Class - • Classes are a blueprint or a set of instructions to build a specific type of object • It is a basic concept of Object-Oriented Programming which revolve around the real-life entities • Class determines how an object will behave and what the object will contain • class <class_name> { fields; methods; }; 30
- 31. OBJECT • Object • is an instance of a class • An object in OOPS is nothing but a self-contained component which consists of methods and properties to make a particular type of data useful • For example color name, table, bag, barking • When you send a message to an object, you are asking the object to invoke or execute one of its methods as defined in the class • Syntax: • Classname variable_name = new Classname(); 31
- 32. CLASS VS OBJECTS • A Class • In object oriented programming class is a blueprint or prototype that defines the variables and the methods (functions) common to all Objects of a certain kind • An object • In OOPS object is a specimen of a class • Software objects are often used to model real-world objects you find in everyday life 32
- 33. INHERITANCE • Inheritance – • Inheritance can be defined as the process where one class acquires the properties, methods and fields of another • With the use of inheritance the information is made manageable in a hierarchical order • The class which inherits the properties of the other is known as subclass, derivedclass, childclass and the class whose properties are inherited are known as superclass, baseclass, parentclass 33
- 34. POLYMORPHISM • Polymorphism – • Allows us to use the same word to mean different things in different contexts • The capability of a method to do different things and take on many forms based on the object that it is acting upon • In other words, polymorphism allows you define one interface (or class) and have multiple implementations 34
- 35. ABSTRACTION • Abstraction- • Allows for simple things to represent complexity • Such as objects, classes, and variables representing more complex underlying code and data • We all know how to turn the TV on, but we don’t need to know how it works in order to enjoy it • For example in our code we could create a TV object then ask it to turn on. We don’t need to worry about how the TV object works as long as we know it has a on method within • Consider the scanner import – we don’t worry about how it works we just create a scanner object and use it when we want user input • This is important because it lets avoid repeating the same work multiple times. 35
- 36. ENCAPSULATION • Encapsulation – • Encapsulation is a mechanism of wrapping the data variables and code acting on the data methods together as a single unit • The variables of a class will be hidden from other classes, and can be accessed only through the methods of their current class, therefore it is also known as data hiding • To achieve encapsulation, we declare the variables of a class as private • Provide public setter and getter methods to modify and view the variables values • We can re-use objects like code components or variables without allowing open access to the data system-wide 36
- 38. ADVANTAGES • Code Reusability • Represents generic application concepts closely and are more near to real world models • Ease of programming • Ease of Maintenance • Ease in extension • Ease in redesign • Portability • Scalability • Compatibility with C • Memory Management 38
- 39. DISADVANTAGES • Designing OOP program is more tricky • Planning in more important • Good skills (Designing skills, Programming Skills and Thinking Skills) need to acquired by the programmer • Absence of Garbage Collector • No Built-in threads • Use of Pointers 39
- 40. THE END