1. Write two major differences between Object-oriented programming and procedural programming?

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1 1. Write two major differences between Object-oriented programming and procedural programming? A procedural program is written as a list of instructions, telling the computer, step-by-step, what to do: Open a file, read a number, multiply by 4, display something. Program units include the main or program block, subroutines, functions, procedures; file scoping; includes/modules; libraries. OOP achieves its goal of overcoming the drawbacks of procedural programming. An object-oriented programming language (also called an OO language) is one that allows or encourages, to some degree, object-oriented programming techniques such as encapsulation, inheritance, modularity, and polymorphism. 2. What is abstraction? Abstraction refers to the act of representing essential features without including the background details or explanation. 3. What do you understand by programming paradigm? What are the various programming paradigms? A programming paradigm defines the methodology of designing and implementing programs using the key features and building blocks of a programming language. The various programming paradigms are: Procedural programming, Object based programming and Object-oriented programming. 4. What are the characteristics of procedural programming? Procedural programming is fine for small projects. It is the most natural way to tell a computer what to do, and the computer processor's own language, machine code, is procedural, so the translation of the procedural high-level language into machine code is straightforward and efficient. The procedural programming has a built-in way of splitting big lists of instructions into smaller lists: the function. 5. What is an object? What is a class? How is an object different from a class? Object is an identifiable entity with some characteristics and behavior. A class is a group of objects that share common properties and relationships. Car is not an object. We can say the Santro is an object of class type car where Car is a class. 6. What is Object-oriented programming paradigm? Name the four basic concepts of OOP. 1

2 OOP achieves its goal of overcoming the drawbacks of procedural programming. An object-oriented programming language (also called an OO language) is one that allows or encourages, to some degree, object-oriented programming techniques such as encapsulation, inheritance, modularity, and polymorphism. 7. What is meant by abstraction? Abstraction refers to the act of representing essential features without including the background details or explanations. 8. What is encapsulation? Why is data considered safe if encapsulated? It is the way of wrapping up of data and functions that operate on that data under a single unit. The class groups its members into three categories: private, protected and public. The private and the protected members are hidden from the outside world. Thus, class enforces data hiding. 9. How are the terms abstraction and encapsulation related? Using the method of encapsulation, the programmer cannot directly access the data. Data is only accessible through the functions present inside the class. Data encapsulation leads to the important concept of data hiding. Data hiding is the implementation details of a class that are hidden from the user. 10. What is a base class? What is a subclass? What is the relationship between a base class and subclass? Inheritance is implemented in C++ by specifying the name of the base class from which the derived class is to be created. The relationship is parent-child-relationship. 11. How does inheritance support reusability? The derived classes have all the features of the base class and the programmer can choose to add new features specific to the newly created derived class. 12. What do you mean by the transitive nature of inheritance? Inheritance is one of the important concepts of object-oriented language. There are several reasons why this concept was introduced in object- oriented language. Some major reasons are: (i) The capability to express the inheritance relationship which ensures the closeness with the real world model. (ii) Idea of reusability, i.e., the new class can use some of the features of the old class. (iii) Transitive nature of inheritance, i.e., it can be passed on further. 2

3 13. How are the object s characteristics represented in software terms? How are object s behavior represented in software terms? The main aim is to implement real world object as software object. The Real-world objects have physical characteristics (state) and behavior (methods). 14. How is data hiding implemented in C++? The main aim is to implement real world-object as a software object. Real-world objects have physical characteristics (state) and behavior (methods). E.g. a car has: (please fill in the required details)( The example is incomplete). 15. Which construct implements encapsulation in C++? Class is use to describe encapsulation. A class only binds the data and the associated functions together as one unit. 16. What is abstract class? What is concrete class? Abstract classes are classes that contain one or more abstract methods. An abstract method is a method that is declared, but contains no implementation. A concrete class is a class which is derived from the abstract class. 17. Define the following terms: (i) Inheritance (ii) Encapsulation Inheritance is the capacity of one class of things to inherit capabilities or properties from another class. Polymorphism is the ability for a message or data to be processed in more than one form. 18. What is polymorphism? How does function overloading implement polymorphism? Polymorphism is the ability for a message or data to be processed in more than one form. Function overloading refers to the same function name but various operations. 19. Discuss major OOP concepts briefly. The Object-oriented approach views the problem as objects rather than that of procedures. 3

4 Object is an identifiable entity with some characteristics and behavior. For example, we can say Orange is an object. Its characteristics are: it is spherical in shape and it s orange in color. Its behavior is: It is juicy and it tastes sweet-sour. Objects are basic runtime entities in an object- oriented system. They may represent a person, a place, a bank account, a table of data or any item that must be handled. Program should make a communication between objects. A group of objects that share common properties and relationships. We just mentioned that objects contain data and code to manipulate that data. The entire set of data and code of an object can be made a user-defined data type with the help of a class. A class is a collection of objects of a similar type. Data Abstraction Abstraction refers to the act of representing essential features without including the background detail or explanation. Data encapsulation It is the way of wrapping up data and functions that operate on that data under a single unit. Encapsulation is the process of combining data and functions into a single unit called class. Modularity Modularity is the property of a system that has been decomposed into a set of interconnected and loosely joined modules. For example, you must have seen a music system which consists of a cd player, a cassette-player, recorder-player, tuner, speaker, etc. These parts are a complete unit by itself but subparts of the music system. This is how modularity works in OOPS. Inheritance: Inheritance is the capacity of one class of things to inherit capabilities or properties from another class. Inheritance is the process by which new classes called derived classes are created from existing classes called base classes. The derived classes have all the features of the base class and the programmer can choose to add new features specific to the newly created derived class. Polymorphism Polymorphism is the ability for a message or data to be processed in more than one form. Polymorphism is the ability to use an operator or function in different ways. Poly, referring to many, signifies the many uses of these operators and functions. A single function usage or an operator functioning in many ways can be called polymorphism. Polymorphism refers to codes, operations or objects that behave differently in different contexts. 20. What is programming paradigms? Give the names of popular programming paradigms. 4

5 A programming paradigm is a fundamental style of writing computer programs. This is the methodology of designing and implementing programs using the key features and other building blocks of a programming language. A programming paradigm gives us an idea of analyzing and solving the problem using programming language. A programming paradigm defines the methodology of designing and implementing programs using key features and building blocks of a programming language. The various programming paradigms are: Procedural programming, Object based programming and Object-oriented programming. 21. What are the short comings of procedural and modular programming? Modularity is generally desirable, especially in large, complicated programs. Inputs are usually specified syntactically in the form of arguments and the outputs delivered as return values. Scoping is another technique that helps keep procedures strongly modular. It prevents the procedure from accessing the variables of other procedures (and vice-versa), including previous instances of itself, without explicit authorization. Less modular procedures, often used in small or quickly written programs, tend to interact with a large number of variables in the execution environment, which other procedures might also modify. Due to the ability to specify a simple interface, to be self-contained, and to be reused, procedures are a convenient vehicle for making pieces of code written by different people or different groups, including through programming libraries. 22. Write a short note on OO programming. The object-oriented programming paradigm is superset of object based programming. Objectoriented programming language overcomes the limitation of object based programming language by implementing inheritance. The various categories of OOP Pure OO languages, everything in them is treated consistently as an object, from primitives such as characters and punctuation, all the way up to whole classes, prototypes, blocks, modules, etc. Languages are designed mainly for OO programming, but with some procedural elements. Languages with most of the features of objects (classes, methods, inheritance, reusability), but in a distinctly original form. Languages with abstract data type support, but not all features of object-orientation, sometimes called object-based languages. 23. How does OOP overcome the shortcomings of the traditional programming approach? 5

6 The focus of procedural programming is to break down a programming task into a collection of variables, data structures, and subroutines, whereas in object-oriented programming - it is to break down a programming task into objects. Either method can be valid for accomplishing a specific programming task. object-oriented methods objects message attribute functions modules argument variable procedural The most important distinction is procedural programming uses procedures to operate on data structures, object-oriented programming bundles the two together so an "object" operates on its "own" data structure. 24. Write a note on Inheritance. Inheritance: Inheritance is the capacity of one class of things to inherit capabilities or properties from another class. Inheritance is the process by which new classes called derived classes are created from existing classes called base classes. The derived classes have all the features of the base class and the programmer can choose to add new features specific to the newly created derived class. For example, a programmer can create a base class named fruit and define derived classes as mango, orange, banana, etc. Each of these derived classes, (mango, orange, banana, etc.) has all the features of the base class (fruit) with additional attributes or features specific to these newly created derived classes. Mango would have its own defined features, orange would have its own defined features, banana would have its own defined features, etc. 25. What are the advantages offered by inheritance? Features or Advantages of Inheritance: Reusability: Inheritance helps the code to be reused in many situations. The base class is defined and once it is compiled, it need not be reworked. Using the concept of inheritance, the programmer can create as many derived classes from the base class as needed while adding specific features to each derived class as needed. Saves Time and Effort: The above concept of reusability achieved by inheritance saves the programmer time and effort. The main reason is that the main code that is written can be reused in various situations as needed. Increases Program Structure which results in greater reliability. 6

7 26. Do you think OOP is closer to real world problems? Why? How? Yes, OOP is closer to real world problems. Let us take a small example of cooking dinner. We are planning to make chapatti, dhal, vegetable subji, rice, potato fry, etc. We have to write a program for it. Using procedural programming paradigm, we ll write a separate program for each recipe and each program will have instructions for using the steamer as a steamer is used to do all the boiling work. But, we don t want to do the code repetition. Once we have written the code its better we reuse it in all places. But it is not possible in case of procedural programming. However, it is solved using the Object-Oriented approach. 27. How are classes and objects implemented in C++? The data and behavior are packed together as classes. Abstraction is relative to the purpose and the user. Class is the software representation of abstraction. An object is an instance of the data type class. Software code in OOP is always pertaining to the class, object and the ways to manipulate the object. Implementing objects The main aim is to implement real world object as software object. In the real world, the objects have physical characteristics(state) and behavior(methods). E.g. a car has: Characteristics: four wheels, number of gears, steering, etc. Behavior: braking, speed, accelerating, etc. A class is defined as: Class <class-name> { }; 28. While implementing encapsulation, abstraction is also implemented. Comment. Yes, while implementing encapsulation, abstraction is also implemented. It is the way of wrapping up data and function that operate on that data under a single unit. Rules to be followed while encapsulating: 1. The attributes that the object doesn t posses is excluded. 2. The unimportant implementation details are hidden. 3. Class is used to describe encapsulation. 29. Discuss the relationship between abstract and concrete class. 7

8 Abstract classes are classes that contain one or more abstract methods. An abstract method is a method that is declared, but contains no implementation. Abstract classes may not be instantiated, and require subclasses to provide implementations for the abstract methods. Let's look at an example of an abstract class, and an abstract method. Suppose we were modeling the behaviour of animals, by creating a class hierarchy that started with a base class called Animal. Animals are capable of doing different things like flying, digging and walking, but there are some common operations as well like eating and sleeping. Some common operations are performed by all animals, but in a different way as well. When an operation is performed in a different way, it is a good candidate for an abstract method (forcing subclasses to provide a custom implementation). Let's look at a very primitive Animal base class, which defines an abstract method for making a sound (such as a dog barking, a cow mooing, or a pig grunting). You may be wondering why not declare an abstract class as an interface, and have the Dog and Cow implement the interface. Sure you could - but you'd also need to implement eating and sleeping methods. This is done using a concrete class which is derived from the abstract class. So we shall have the method for sound that is required before we implement it. 30. Illustrate the concept of inheritance with an example. Inheritance is the process by which new classes called derived classes are created from existing classes called base classes. The derived classes have all the features of the base class and the programmer can choose to add new features specific to the newly created derived class. For example, a programmer can create a base class named fruit and define derived classes as mango, orange, banana, etc. Each of these derived classes, (mango, orange, banana, etc.) has all the features of the base class (fruit) with additional attributes or features specific to these newly created derived classes. Mango would have its own defined features, orange would have its own defined features, banana would have its own defined features, etc. Again, the example for class where the type of car inherits some of the properties from the class automobiles which inherits some of its properties from another class vehicles. 31. Encapsulation is one of the major properties of OOP. How is this implemented in C++? It is the way of wrapping up of data and function that operate on that data under a single unit. Rules to be followed while encapsulating: The attributes where the object doesn t posses is excluded. The unimportant implementation details are hidden. Class is used to describe encapsulation. A class only binds the data and the associated functions together as one unit. The main aim is to implement real-world object as software object. Real world objects have physical characteristics (state) and behavior (methods). E.g. a car has:( The example is incomplete). Please fill in the details. 8

9 A class is defined as Class <class-name> { private: protected: public: }; 32. Reusability of classes is one of the major properties of OOP? How is it implemented in C++? Inheritance is implemented in C++ by specifying the name of the parent class from which the child class is to be created. Syntax Class <child class name>:<parent class name> { child class s own features } 33. How is polymorphism implemented in C++? Polymorphism is an attribute that allows one interface to be used with different situations. In C++, polymorphism is implemented using virtual functions, operator overloading and function overloading. A virtual function is a member function of a class, whose functionality can be over-ridden in its derived classes. It is one that is declared as virtual in the base class using the virtual keyword. Function overloading refers to the same function name but various operations. This implies to the operator overloading too. 34. Write briefly about different programming paradigms. A programming paradigm is a fundamental style of writing computer programs. This is the methodology of designing and implementing programs using key features and other building blocks of a programming language. A programming paradigm gives us an idea of analyzing and solving the problem using programming language. 9

10 A programming paradigm defines the methodology of designing and implementing programs using the key features and building blocks of a programming language. Procedural Programming The traditional programming languages, which students usually learn first are procedural languages. These include C, C++, Fortran, Pascal, and Basic. A procedural program is written as a list of instructions, telling the computer, step-by-step, what to do: Open a file, read a number, multiply by 4, display something. Program units include the main or program block, subroutines, functions, procedures; file scoping; includes/modules; libraries. Procedural programming is fine for small projects. It is the most natural way to tell a computer what to do, and the computer processor's own language, machine code, is procedural, so the translation of the procedural high-level language into machine code is straightforward and efficient. The procedural programming has a built-in way of splitting big lists of instructions into smaller lists: the function. Object based programming Object based programming is the style of programming that primarily supports encapsulation and object identity. Major features of object based programming are: Data encapsulation Data hiding and access mechanisms Automatic initialization and clear-up of objects Operator overloading Advantages and disadvantages of the object based programming language Advantages: Overcomes the shortcoming of procedural language Implements data abstraction and data hiding Supports user-defined data types Disadvantage It does not support inheritance Object-oriented programming language The object-oriented programming paradigm is superset of object based programming. Objectoriented programming language overcomes the limitation of object based programming language by implementing inheritance. The various categories of OOP Pure OO languages, because everything in them is treated consistently as an object, from primitives such as characters and punctuation, all the way up to whole classes, prototypes, blocks, modules, etc. Languages designed mainly for OO programming, but with some procedural elements. Languages with most of the features of objects (classes, methods, inheritance, reusability), but in a distinctly original form. 10

11 Languages with abstract data type support, but not all features of object-orientation, sometimes called object-based languages. 35. Discuss OOP concepts. How are these implemented in software terms in C++? Let us take a small example of cooking for dinner. We are planning to make chapatti, dhal, vegetable subji, rice, potato fry, etc. We have to write a program for it. Using procedural programming paradigm, we ll write a separate program for each recipe and each program will have an instruction for using the steamer which is used to do all the boiling work. But we don t want to do code repetition. Once we have written the code - its better we reuse it in all places. But it s not possible in case of procedural programming. However, it is solved using the Object-Oriented approach. The Object-oriented approach views the problem as objects rather than that of procedures. Object is an identifiable entity with some characteristics and behavior. From the above mentioned problem of cooking, in the OOP approach, will be viewed in terms of objects involved i.e., steamer, oven, gas, etc., and its interface as the operation it performs. This results in simpler programs at a reduced software cost. For example, we can say Orange is an object. Its characteristics are: it is spherical in shape and itis orange in color. Its behavior is: it is juicy and it tastes sweet-sour. Objects are basic runtime entities in a object-oriented system. They may represent a person, a place, a bank account, a table of data or any item that must be handled. Program should make a communication between objects. Definition: A group of objects that share common properties and relationships. We just mentioned that objects contain data and code to manipulate that data. The entire set of data and code of an object can be made as a user-defined data type with the help of a class. A class is a collection of objects of similar type. From the above example, orange is an object but car is not an object. We can say Santro is an object of class type car. Object is an instance of the class. Basic concepts of OOP OOP achieves its goal of overcoming the draw backs of procedural programming. An object-oriented programming language (also called an OO language) is one that allows or encourages, to some degree, object-oriented programming techniques such as encapsulation, inheritance, modularity, and polymorphism. Data Abstraction Definition abstraction refers to the act of representing essential features without including the background details or explanations. Abstraction is one of the most powerful and vital features provided by object-oriented C++ programming language. The concept of abstraction relates to the idea of hiding data that are not needed for presentation. The main idea behind data abstraction is to give a clear separation between 11

12 properties of data type and the associated implementation details. Thus, abstraction forms the basic platform for the creation of user-defined data types called objects. Data abstraction is the process of refining data to its essential form. An Abstract Data Type is defined as a data type that is defined in terms of the operations that it supports but not in terms of its structure or implementation. In object-oriented programming language C++, it is possible to create and provide an interface that accesses only certain elements of data types. The programmer can decide which user to give or grant access to and hide the other details. This concept is called data hiding which is similar in concept to data abstraction. Let us take the TV as an example. We watch the TV, change channels, increase and decrease the volume, switch it on and off, etc., but while watching, we don t get the internal details of the TV like wiring, picture, if the bulb is working, etc. What s happening inside is hidden from us. This is abstraction where you only know essential things to watch the TV without knowing the background detail or explanation. Data encapsulation It is the way of wrapping up of data and function that operate on that data under a single unit. Encapsulation is the process of combining data and functions into a single unit called class. Using the method of encapsulation, the programmer cannot directly access the data. Data is only accessible through the functions present inside the class. Data encapsulation leads to the important concept of data hiding. Data hiding is the implementation details of a class that are hidden from the user. The concept of restricted access led programmers to write specialized functions or methods for performing the operations on hidden members of the class. Attention must be paid to ensure that the class is designed properly. Example: In the school, the class teachers maintain the attendance of the students of their class. When the class teacher of standard XI wants to know the attendance of a particular student in standard XII then the teacher has to approach the class teacher of standard XII to get details. The class teacher of XI cannot get details on her own authority. Modularity: The method of partitioning a program into individual units is called modularity. The reasons for partitioning a program are: It reduces complexity of the program to a certain extent. It creates well-defined,documented boundaries within the program. A module is a separate unit by itself. It can be compiled separately, though, it has connections with other modules. Modules are inter-connected to achieve the goal. Modularity is the property of a system that has been decomposed into a set of interconnected and loosely joined modules. For example, you must have seen a music system which consists of a cd player, cassette-player, recorder-player, tuner or a speaker, etc. These parts make a complete unit when put together. But, by themselves they are subparts of the music system. This is how modularity works in OOPS. Inheritance: Inheritance is the capacity of one class of things to inherit capabilities or properties from another 12

13 class. Inheritance is the process by which new classes called derived classes are created from existing classes called base classes. The derived classes have all the features of the base class and the programmer can choose to add new features specific to the newly created derived class. For example, a programmer can create a base class named fruit and define derived classes as mango, orange, banana, etc. Each of these derived classes, (mango, orange, banana, etc.) has all the features of the base class (fruit) with additional attributes or features specific to these newly created derived classes. Mango would have its own defined features, orange would have its own defined features, banana would have its own defined features, etc. Again the example, class car inherits some of the properties from the class automobiles which inherits some of its properties from another class vehicles. Features or Advantages of Inheritance: Reusability Saves Time and Effort Increases Program Structure which results in greater reliability Polymorphism Polymorphism is the ability for a message or data to be processed in more than one form. Polymorphism is the ability to use an operator or function in different ways. Poly, referring to many, signifies the many uses of these operators and functions. A single function usage or an operator functioning in many ways can be called polymorphism. Polymorphism refers to codes, operations or objects that behave differently in different contexts. Polymorphism is a powerful feature of the object-oriented programming language in C++. A single operator + behaves differently in different contexts such as integer, float or strings referring the concept of polymorphism. Polymorphism refers to the ability to call different functions by using only one type of function call. Suppose a programmer wants to code vehicles of different shapes such as circles, squares, rectangles, etc. One way to define each of these classes is to have a member function for each that makes vehicles of each shape. Another convenient approach that the programmer can take is to define a base class named Shape and then create an instance of that class. Features and Advantages of the concept of Polymorphism: Helps in reusability of code. Provides easier maintenance of applications. Helps in achieving robustness in applications. 13