Example of Object in Object Oriented Programming
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OOP with Java 16
OOP with Java 16. Inheritance and Overriding Thomas Weise · 汤卫思 [email protected] · http://iao.hfuu.edu.cn Hefei University, South Campus 2 合肥学院 南艳湖校区/南2区 Faculty of Computer Science and Technology 计算机科学与技术系 Institute of Applied Optimization 应用优化研究所 230601 Shushan District, Hefei, Anhui, China 中国 安徽省 合肥市 蜀山区 230601 Econ. & Tech. Devel. Zone, Jinxiu Dadao 99 经济技术开发区 锦绣大道99号 Outline 1 Introduction 2 Extending Classes and Class Hierarchy 3 Multi-Level Inheritance 4 The Class Object 5 static vs. instance methods 6 Summary website OOPwithJava ThomasWeise 2/23 Introduction • So far, we have basically treated as objects as data structures and used methods to work on them OOPwithJava ThomasWeise 3/23 Introduction • So far, we have basically treated as objects as data structures and used methods to work on them • But Object-Oriented Programming is much more OOPwithJava ThomasWeise 3/23 Introduction • So far, we have basically treated as objects as data structures and used methods to work on them • But Object-Oriented Programming is much more • The true power of OOP arises from class inheritance and extension (often called specialization) OOPwithJava ThomasWeise 3/23 Extending Classes • A class Student can extend another class Person OOPwithJava ThomasWeise 4/23 Extending Classes • A class Student can extend another class Person • Student inherits all the fields and functionality of the original class Person OOPwithJava ThomasWeise 4/23 Extending Classes • A class Student can extend another class Person • Student inherits all the fields and functionality -
Operator Overloading ______
Chapter 10: Operator Overloading _________________________________________________________________________________________________________ Consider the following C++ code snippet: vector<string> myVector(kNumStrings); for(vector<string>::iterator itr = myVector.begin(); itr != myVector.end(); ++itr) *itr += "Now longer!"; Here, we create a vector<string> of a certain size, then iterate over it concatenating “Now longer!” to each of the strings. Code like this is ubiquitous in C++, and initially does not appear all that exciting. However, let's take a closer look at how this code is structured. First, let's look at exactly what operations we're performing on the iterator: vector<string> myVector(kNumStrings); for(vector<string>::iterator itr = myVector.begin(); itr != myVector.end(); ++itr) *itr += "Now longer!"; In this simple piece of code, we're comparing the iterator against myVector.end() using the != operator, incrementing the iterator with the ++ operator, and dereferencing the iterator with the * operator. At a high level, this doesn't seem all that out of the ordinary, since STL iterators are designed to look like regular pointers and these operators are all well-defined on pointers. But the key thing to notice is that STL iterators aren't pointers, they're objects, and !=, *, and ++ aren't normally defined on objects. We can't write code like ++myVector or *myMap = 137, so why can these operations be applied to vector<string>::iterator? Similarly, notice how we're concatenating the string “Now longer!” onto the end of the string: vector<string> myVector(kNumStrings); for(vector<string>::iterator itr = myVector.begin(); itr != myVector.end(); ++itr) *itr += "Now longer!"; Despite the fact that string is an object, somehow C++ “knows” what it means to apply += to strings. -
Compile-Time Safety and Runtime Performance in Programming Frameworks for Distributed Systems
Compile-time Safety and Runtime Performance in Programming Frameworks for Distributed Systems lars kroll Doctoral Thesis in Information and Communication Technology School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm, Sweden 2020 School of Electrical Engineering and Computer Science KTH Royal Institute of Technology TRITA-EECS-AVL-2020:13 SE-164 40 Kista ISBN: 978-91-7873-445-0 SWEDEN Akademisk avhandling som med tillstånd av Kungliga Tekniska Högskolan fram- lägges till offentlig granskning för avläggande av teknologie doktorsexamen i informations- och kommunikationsteknik på fredagen den 6 mars 2020 kl. 13:00 i Sal C, Electrum, Kungliga Tekniska Högskolan, Kistagången 16, Kista. © Lars Kroll, February 2020 Printed by Universitetsservice US-AB IV Abstract Distributed Systems, that is systems that must tolerate partial failures while exploiting parallelism, are a fundamental part of the software landscape today. Yet, their development and design still pose many challenges to developers when it comes to reliability and performance, and these challenges often have a negative impact on developer productivity. Distributed programming frameworks and languages attempt to provide solutions to common challenges, so that application developers can focus on business logic. However, the choice of programming model as provided by a such a framework or language will have significant impact both on the runtime performance of applications, as well as their reliability. In this thesis, we argue for programming models that are statically typed, both for reliability and performance reasons, and that provide powerful abstractions, giving developers the tools to implement fast algorithms without being constrained by the choice of the programming model. -
Property Mapping: a Simple Technique for Mobile Robot Programming
Property Mapping: a simple technique for mobile robot programming Illah R. Nourbakhsh The Robotics Institute, Carnegie Mellon University Pittsburgh, PA 15213 [email protected] Abstract In this paper we present robot observability as a The mobile robot programming problem is a software predictor for diagnostic transparency. Then, we present a engineering challenge that is not easily conquered using language-independent technique called property mapping contemporary software engineering best practices. We for constructing robot programs that are diagnostically propose robot observability as a measure of the diagnostic transparent and thereby achieve high degrees of transparency of a situated robot program, then describe reliability. property mapping as a simple, language-independent approach to implementing reliable robot programs by maximizing robot observability. Examples from real- The Robot Programming Problem world, working robots are given in Lisp and Java. A mobile robot is a situated automata, or a module that comprises one part of a closed system together with the Introduction environment. Fig. 1 shows the standard depiction of a robot, with its outputs labeled as actions and the outputs The recent availability of inexpensive, reliable robot of the environment in turn labeled as percepts. chassis (e.g. ActivMedia Pioneer, IS-Robotics Magellan, Nomad Scout) has broadened the accessibility of mobile robotics research. Because these robots consist of fixed E hardware out-of-the-box, this technology is shifting the actions A P percepts emphasis of mobile robot research from a joint hardware and software design process toward hardware-unaware R mobile robot programming. This is a software design problem, and yet software Figure 1: The standard view of an embedded robot engineering best practices are not very helpful. -
Programming in JAVA Topic: • a Closer Look at Methods And
B. Sc. (H) Computer Science Semester II BHCS03 – Programming in JAVA Topic: A Closer Look at Methods and Classes Inheritance Command Line Arguments The java command-line argument is an argument i.e. passed at the time of running the java program. The arguments passed from the console can be received in the java program and it can be used as an input. So, it provides a convenient way to check the behavior of the program for the different values. You can pass N (1,2,3 and so on) numbers of arguments from the command prompt. Simple example of command-line argument In this example, we are receiving only one argument and printing it. To run this java program, you must pass at least one argument from the command prompt. class CommandLineExample{ public static void main(String args[]){ System.out.println("Your first argument is: "+args[0]); } } compile by > javac CommandLineExample.java run by > java CommandLineExample sonoo Output: Your first argument is: sonoo Varargs: Variable length arguments A method with variable length arguments(Varargs) in Java can have zero or multiple arguments. Variable length arguments are most useful when the number of arguments to be passed to the method is not known beforehand. They also reduce the code as overloaded methods are not required. Example public class Demo { public static void Varargs(String... str) { System.out.println("\nNumber of arguments are: " + str.length); System.out.println("The argument values are: "); for (String s : str) System.out.println(s); } public static void main(String args[]) { Varargs("Apple", "Mango", "Pear"); Varargs(); Varargs("Magic"); } } Output Number of arguments are: 3 The argument values are: Apple Mango Pear Number of arguments are: 0 The argument values are: Number of arguments are: 1 The argument values are: Magic Overloading Varargs Methods Overloading allows different methods to have same name, but different signatures where signature can differ by number of input parameters or type of input parameters or both. -
C++ Properties -- a Library Solution
Document Number: SC22/WG21/N1615=04-0055 Date: 2004-04-09 Author: Lois Goldthwaite Email: [email protected] C++ Properties -- a Library Solution N1600 is a summary of the "property" language extension that is proposed for C++/CLI. I can't help feeling that this is an effort to impose an alien idiom on C++. There is too much of "the compiler will perform black magic behind your back" in it. There are too many ways in which the programmer must be aware that some [pseudo-]data members must be handled in different ways from [real] data members. The C++/CLI draft spec (N1608)says in 8.8.4 and 18.4 that "A property is a member that behaves as if it were a field." I think "behaves" is absolutely the wrong word to use here. A property is behavior that pretends to be state. From an OO design point of view, I think this is A Bad Idea. Behaviour should be visible; state should not. Further on, the document continues, "the X and Y properties can be read and written as though they were fields. In the example above, the properties are used to implement data hiding within the class itself." The subtle advantage of "hiding" a private data member by treating it as a public data member escapes me. Properties are just syntactic saccharine for getter and setter member functions for individual fields. C++ experts have spent years trying to educate people NOT to use public data, to use member functions instead, and now we propose to introduce something that looks just like public data? Do we really want to try to teach people that public fields are still bad, but properties are good, even though they look just the same from outside the class? Moreover, these public fields have side effects! There is a danger that too many novice programmers will prototype their designs using public fields, with the intent of changing them to properties later, if and when it proves necessary, and the general quality of code will suffer because of it. -
Comparative Studies of Programming Languages; Course Lecture Notes
Comparative Studies of Programming Languages, COMP6411 Lecture Notes, Revision 1.9 Joey Paquet Serguei A. Mokhov (Eds.) August 5, 2010 arXiv:1007.2123v6 [cs.PL] 4 Aug 2010 2 Preface Lecture notes for the Comparative Studies of Programming Languages course, COMP6411, taught at the Department of Computer Science and Software Engineering, Faculty of Engineering and Computer Science, Concordia University, Montreal, QC, Canada. These notes include a compiled book of primarily related articles from the Wikipedia, the Free Encyclopedia [24], as well as Comparative Programming Languages book [7] and other resources, including our own. The original notes were compiled by Dr. Paquet [14] 3 4 Contents 1 Brief History and Genealogy of Programming Languages 7 1.1 Introduction . 7 1.1.1 Subreferences . 7 1.2 History . 7 1.2.1 Pre-computer era . 7 1.2.2 Subreferences . 8 1.2.3 Early computer era . 8 1.2.4 Subreferences . 8 1.2.5 Modern/Structured programming languages . 9 1.3 References . 19 2 Programming Paradigms 21 2.1 Introduction . 21 2.2 History . 21 2.2.1 Low-level: binary, assembly . 21 2.2.2 Procedural programming . 22 2.2.3 Object-oriented programming . 23 2.2.4 Declarative programming . 27 3 Program Evaluation 33 3.1 Program analysis and translation phases . 33 3.1.1 Front end . 33 3.1.2 Back end . 34 3.2 Compilation vs. interpretation . 34 3.2.1 Compilation . 34 3.2.2 Interpretation . 36 3.2.3 Subreferences . 37 3.3 Type System . 38 3.3.1 Type checking . 38 3.4 Memory management . -
Rexx Interview Questions That Can Help You Ace Your Rexx Interview
By OnlineInterviewQuestions.com Rexx is the acronym for Restructured Extended Executor. It is a high-level programming language developed by Mike Cowlishaw to make learning and reading easier. There are multiple applications of Rexx. It is used as scripting and for processing data. It is also as an internal macro language in some software like THE and ZOC. Rexx is a versatile programming language and can be mixed with various commands to different host environments. It is a very useful language for beginners and the demand for experienced computer professionals is growing exponentially. This blog covers important Rexx interview questions that can help you ace your Rexx interview. If you wish to stand out from the crowd, these interview questions are your best friend. Q1. What is Uni-REXX? Uni-REXX is a UNIX implementation of Rexx programming language which offers rich sets of functions that are particularly designed for UNIX environment. Uni-REXX is now available on SUN’s Solaris 7/8/9, H/P’s HP/UX 10/11, IBM’s AIX 4/5, SGI’s IRIX 5/6, NCR UNIX, Linux Intel and S/390. It is used for several purposes such as automating system administration tasks. It also helps in development for end-user applications and rapid-prototyping of complied-language applications. Q2. Enlist the features of Rexx as a programming language. Following are the few features of Rexx- Rexx language has a very simple syntax format. Rexx can support multiple functions, procedures and route commands to several environments. It comes with very few artificial limitations and provides crash protection. -
Module 3 Inheritance in Java
Module 3 Inheritance in Java Inheritance in java is a mechanism in which one object acquires all the properties and behaviors of parent object. The idea behind inheritance in java is that you can create new classes that are built upon existing classes. When you inherit from an existing class, you can reuse methods and fields of parent class, and you can add new methods and fields also. Inheritance represents the IS-A relationship, also known as parent-child relationship. For Method Overriding (so runtime polymorphism can be achieved). For Code Reusability. Syntax of Java Inheritance class Subclass-name extends Superclass-name { KTUNOTES.IN //methods and fields } The extends keyword indicates that you are making a new class that derives from an existing class. In the terminology of Java, a class that is inherited is called a super class. The new class is called a subclass. As displayed in the above figure, Programmer is the subclass and Employee is the superclass. Relationship between two classes is Programmer IS-A Employee.It means that Programmer is a type of Employee. class Employee{ float salary=40000; } class Programmer extends Employee{ int bonus=10000; public static void main(String args[]){ Programmer p=new Programmer(); System.out.println("Programmer salary is:"+p.salary); System.out.println("Bonus of Programmer is:"+p.bonus); } } Programmer salary is:40000.0 Bonus of programmer is:10000 In the above example, Programmer object can access the field of own class as well as of Employee class i.e. code reusability. Downloaded from Ktunotes.in Types of inheritance in java On the basis of class, there can be three types of inheritance in java: single, multilevel hierarchical. -
Property Conveyances As a Programming Language
Property Conveyances as a Programming Language Shrutarshi Basu∗ Nate Foster James Grimmelmann Harvard University Cornell University Cornell Law School & Cornell Tech Cambridge, MA, USA Ithaca, NY, USA New York, NY, USA [email protected] [email protected] [email protected] Abstract 1 Introduction Anglo-American law enables property owners to split up Many legal issues depend on vague, open-ended standards. rights among multiple entities by breaking their ownership For example, nuisance law prohibits “unreasonable” interfer- apart into future interests that may evolve over time. The con- ence with neighbors’ use of land. What counts as “unreason- veyances that owners use to transfer and subdivide property able” depends on an eight-factor balancing test, and many of rights follow rigid syntactic conventions and are governed the individual factors are themselves vague and open-ended, by an intricate body of interlocking doctrines that determine including “the social value that the law attaches to the pri- their legal eect. These doctrines have been codied, but mary purpose of the conduct;” and “the suitability of the only in informal and potentially ambiguous ways. particular use or enjoyment invaded to the character of the This paper presents preliminary work in developing a locality.” [American Law Institute 1979] A lawyer who wants formal model for expressing and analyzing property con- to know whether a client’s cement plant will be considered veyances. We develop a domain-specic language capable a nuisance will have to research numerous previous cases, of expressing a wide range of conveyances in a syntax ap- gather extensive facts about the plant and its neighbors, and proximating natural language. -
Dealing with Properties
Dealing with Properties Martin Fowler [email protected] lmost every object you create needs properties: some statement about the object. A person may have a height, a company may have a CEO, a flight may have a flight Anumber. There are a number of ways to model properties. In this article I will explore some of these ways and when you may want to use them. I’ve often seen patterns touch on this subject, but they usually only cover part of the picture. Here I want to cover the issue more broadly to give a better discussion of the options. The most common, and the simplest case is to use a Fixed Property, that is just declare the attribute on the class. In the vast majority of cases that is all you need to do. Fixed properties begin to fail when you have a large amount of them, or you need to change them frequently, possibly at run time. These forces lead you to the varieties of Dynamic Property. All dynamic properties have the quality of a parameterized attribute where to query a property you need to use a query method with a parameter. The simplest of these is the Flexible Dynamic Property where the parameter is just a string. This makes it easy to define and use properties, but is difficult to control. If you need that control you can use a Defined Dynamic Property where your parameters must be instances of some class. A further step of control allows you to strongly type your dynamic property with a Typed Dynamic Property. -
Alice Glossary
Adventures in Alice Programming // Glossary of Useful Terms by Michael Marion // July 2012 Worlds, methods, functions, properties, variables - it’s pretty easy to get all of the terminology and concept matter confused when it comes to programming in Alice. To that point, we’ve developed this handy reference to use. Hopefully it helps you not to get mixed up. Enjoy! World A world in Alice encompasses everything. Just as we’d say that everyone and everything exists in our world in real life; every object, method, event, or anything else lies inside the world in Alice. The whole .a2w file represents the world. Object An object is just what it sounds like. Any sort of three-dimensional shape such as a person, animal, piece of furniture, building, or anything else of the sort in your world is an object. Most objects are added to the world via the Add Objects button, but some - the ground, camera, and light, for instance - are there by default. There are also two-dimensional objects such as text and billboards. Properties An object’s properties are also what they sound like. All objects have certain properties - whether or not they’re showing, their color, their position, and so forth. Color Defines the color of an object. There is a limited number of color choices in Alice, but it covers all primary colors and some extras, including red, blue, green, yellow, black, and cyan. To specify a white object, select “no color”. Opacity Defines the transparency of an object. Unlike isShowing, setting the opacity to a middle amount allows it to be only slightly transparent.