OOP terminology 2023 with complete solution questions and answers

Program Modules Program development requires that large programs are divided into smaller program modules to be manageable. This is the principle of divide and conquer. Structured Programming Structured programming is an organized style of programming that places emphasis on modular programming, which aids testing, debugging and modifying. In structured programming, modules are procedures and functions that process external data passed by parameters Object Oriented Programming is a programming style with heavy emphasis on program reliability through modular programming. In object oriented programming, modules contain both the data and subroutines that process the data. In Java the modules are called classes and the process-subroutines are smaller modules called methods. Object Oriented Programming, a formal definition is a style of programming that incorporates program development in a language with the following three OOP traits: • Encapsulation • Polymorphism • Inheritance Encapsulation is the process of placing a data structure's data (attributes) with the methods (actions) that act upon the data, inside the same module, called a class in Java. Inheritance is the process of using features (both attributes and actions) from an established higher class. The higher class is called the superclass. The lower class is called the subclass. Polymorphism(vague) allows a single accessing feature, such as an operator, method or class identifier, to have many forms Class is a user-defined data type that encapsulates both data and the methods that act upon the data and is a template for the construction of objects. Object or Instance is one instance of a class. A class is a type and an object is a variable. Cat is a class and Fluffy is an object or one instance of the Cat class. Objects can be discussed in a general sense, such as in Object Oriented Programming. This causes confusion between Object, the concept and object, the instance of a class. There is a tendency to use instance when referring to one variable example of a class to avoid confusion. Attributes or Instance Variables The data components of a class are the class attributes and they are also called _________. should only be accessed by methods of the same class. Methods _______are action modules that process data. In other languages such modules may be called subroutines, procedures or functions. In Java the modules are called _______. They are declared inside a class module and process the instance variables. Instantiation is the moment or instance that memory is allocated for a specific object of a class. Statements like the construction of an object, the definition of an object, the creation of an object all have the same meaning as the instantiation of an object. Class Declaration Location is located outside any other class declaration. It is possible to declare one class inside another class (inner class), which is not part of this course. Instantiation and Construction An object is created with the new operator. The creation of a new object is called: instantiation of an object construction of an object The special method that is called during the instantiation of a new object is called a constructor. Private and Public Class Members The principle of encapsulation requires that object data members are only accessed by methods of the same object. Private class members of some object x can only be accessed by methods of the same x object. Public class members of some object x can be accessed by any client of object x. Data attributes of a class should be declared private. Methods of a class are usually declared public, but there are special helper methods that may also be declared private. Helper methods will be demonstrated later in this chapter. Copy Constructor is a constructor that instantiates a new object as a copy of an existing object. A ___________uses a single parameter, which is an object of the same class as the copy constructor. Objects and Simple (Types Store Information Differently) Simple (primitive) data types store assigned values directly in their allocated memory locations. Objects store memory references of the memory locations allocated during the construction of the object Aliasing occurs when two or more variables reference the same memory location. Any change in the value of one variable brings about a change in the value of the other variable(s). Java Parameters Java passes information to a method with parameters. A copy of the calling, actual parameter is assigned to the receiving, formal parameter in the method. In the case of a simple/primitive data type, a copy of the variable's value, like 23, 'A', or true, is sent by the parameter. Any changes are changes to a copy, which makes no changes to the original. The same thing actually happens in the case of an object; however, with an object the value is the memory address of the object itself. If this is changed, it does not alter the memory address of the original object. The only way changes made in a method impact the original calling object, is if changes are made to the attributes of the object. NOTE: Strings are objects, even though they tend to behave like simple/primitive data types in some programs. Class Methods It is possible to access methods directly without first creating an object. Methods that are accessed in this manner are called Class Methods. Class methods need to be declared with the static keyword used in the heading like: public static double add(double a, double b) { return a + b; } Accessing a class method is done with the class identifier, followed by the method identifier, like: Sln(C(X,Y)); It is possible to access static methods with object identifiers. This is considered poor styling and should be avoided. Static Methods and Static Attributes Static methods and static attributes can be accessed for the entire duration of a program. Static variables (attributes) can be accessed by static methods and object methods. Instance variables (attributes) can only be accessed by object methods. Static attributes can be accessed with object identifiers and class identifiers.