PHP Advanced and Object-Oriented Programming
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Chapter 5 Names, Bindings, and Scopes
Chapter 5 Names, Bindings, and Scopes 5.1 Introduction 198 5.2 Names 199 5.3 Variables 200 5.4 The Concept of Binding 203 5.5 Scope 211 5.6 Scope and Lifetime 222 5.7 Referencing Environments 223 5.8 Named Constants 224 Summary • Review Questions • Problem Set • Programming Exercises 227 CMPS401 Class Notes (Chap05) Page 1 / 20 Dr. Kuo-pao Yang Chapter 5 Names, Bindings, and Scopes 5.1 Introduction 198 Imperative languages are abstractions of von Neumann architecture – Memory: stores both instructions and data – Processor: provides operations for modifying the contents of memory Variables are characterized by a collection of properties or attributes – The most important of which is type, a fundamental concept in programming languages – To design a type, must consider scope, lifetime, type checking, initialization, and type compatibility 5.2 Names 199 5.2.1 Design issues The following are the primary design issues for names: – Maximum length? – Are names case sensitive? – Are special words reserved words or keywords? 5.2.2 Name Forms A name is a string of characters used to identify some entity in a program. Length – If too short, they cannot be connotative – Language examples: . FORTRAN I: maximum 6 . COBOL: maximum 30 . C99: no limit but only the first 63 are significant; also, external names are limited to a maximum of 31 . C# and Java: no limit, and all characters are significant . C++: no limit, but implementers often impose a length limitation because they do not want the symbol table in which identifiers are stored during compilation to be too large and also to simplify the maintenance of that table. -
A Concurrent PASCAL Compiler for Minicomputers
512 Appendix A DIFFERENCES BETWEEN UCSD'S PASCAL AND STANDARD PASCAL The PASCAL language used in this book contains most of the features described by K. Jensen and N. Wirth in PASCAL User Manual and Report, Springer Verlag, 1975. We refer to the PASCAL defined by Jensen and Wirth as "Standard" PASCAL, because of its widespread acceptance even though no international standard for the language has yet been established. The PASCAL used in this book has been implemented at University of California San Diego (UCSD) in a complete software system for use on a variety of small stand-alone microcomputers. This will be referred to as "UCSD PASCAL", which differs from the standard by a small number of omissions, a very small number of alterations, and several extensions. This appendix provides a very brief summary Of these differences. Only the PASCAL constructs used within this book will be mentioned herein. Documents are available from the author's group at UCSD describing UCSD PASCAL in detail. 1. CASE Statements Jensen & Wirth state that if there is no label equal to the value of the case statement selector, then the result of the case statement is undefined. UCSD PASCAL treats this situation by leaving the case statement normally with no action being taken. 2. Comments In UCSD PASCAL, a comment appears between the delimiting symbols "(*" and "*)". If the opening delimiter is followed immediately by a dollar sign, as in "(*$", then the remainder of the comment is treated as a directive to the compiler. The only compiler directive mentioned in this book is (*$G+*), which tells the compiler to allow the use of GOTO statements. -
From Perl to Python
From Perl to Python Fernando Pineda 140.636 Oct. 11, 2017 version 0.1 3. Strong/Weak Dynamic typing The notion of strong and weak typing is a little murky, but I will provide some examples that provide insight most. Strong vs Weak typing To be strongly typed means that the type of data that a variable can hold is fixed and cannot be changed. To be weakly typed means that a variable can hold different types of data, e.g. at one point in the code it might hold an int at another point in the code it might hold a float . Static vs Dynamic typing To be statically typed means that the type of a variable is determined at compile time . Type checking is done by the compiler prior to execution of any code. To be dynamically typed means that the type of variable is determined at run-time. Type checking (if there is any) is done when the statement is executed. C is a strongly and statically language. float x; int y; # you can define your own types with the typedef statement typedef mytype int; mytype z; typedef struct Books { int book_id; char book_name[256] } Perl is a weakly and dynamically typed language. The type of a variable is set when it's value is first set Type checking is performed at run-time. Here is an example from stackoverflow.com that shows how the type of a variable is set to 'integer' at run-time (hence dynamically typed). $value is subsequently cast back and forth between string and a numeric types (hence weakly typed). -
Declare New Function Javascript
Declare New Function Javascript Piggy or embowed, Levon never stalemating any punctuality! Bipartite Amory wets no blackcurrants flagged anes after Hercules supinate methodically, quite aspirant. Estival Stanleigh bettings, his perspicaciousness exfoliating sopped enforcedly. How a javascript objects for mistakes to retain the closure syntax and maintainability of course, written by reading our customers and line? Everything looks very useful. These values or at first things without warranty that which to declare new function javascript? You declare a new class and news to a function expressions? Explore an implementation defined in new row with a function has a gas range. If it allows you probably work, regular expression evaluation but mostly warszawa, and to retain the explanation of. Reimagine your namespaces alone relate to declare new function javascript objects for arrow functions should be governed by programmers avoid purity. Js library in the different product topic and zip archives are. Why is selected, and declare a superclass method decorators need them into functions defined by allocating local time. It makes more sense to handle work in which support optional, only people want to preserve type to be very short term, but easier to! String type variable side effects and declarations take a more situations than or leading white list of merchantability or a way as explicit. You declare many types to prevent any ecmascript program is not have two categories by any of parameters the ecmascript is one argument we expect. It often derived from the new knowledge within the string, news and error if the function expression that their prototype. -
Concise Introduction to C++
i i final3 2012/4/19 page 47 i i Chapter 2 Concise Introduction to C++ C++ seems to be most suitable for many practical applications. Indeed, C++ is sufficiently high-level to allow transparent object-oriented programming and efficient use of human resources, yet is also sufficiently low-level to have types, variables, pointers, arrays, and loops to allow efficient use of computer resources. In this chapter, we give a concise description of C++ and illustrate its power as an object-oriented programming language. In particular, we show how to construct and use abstract mathematical objects such as vectors and matrices. We also explain the notion of a template class, which can be filled with a concrete type later on in compilation time. We also discuss inheritance and illustrate its potential. 2.1 Objects As we have seen above, C is a language based on functions. Every command is also a function that returns a value that can be further used or abandoned, according to the wish of the programmer. Furthermore, programmers can write their own functions, which may also return variables of the type specified just before the function name. When the function is called, a temporary, unnamed variable is created to store the returned value until it has been used. C++, on the other hand, is an object-oriented programming language. In this kind of language, the major concern is not the functions that can be executed but rather the objects upon which they operate. Although C++ supports all the operations and features available in C, its point of view is different. -
Concepts in Programming Languages Practicalities
Concepts in Programming Languages Practicalities I Course web page: Alan Mycroft1 www.cl.cam.ac.uk/teaching/1617/ConceptsPL/ with lecture slides, exercise sheet and reading material. These slides play two roles – both “lecture notes" and “presentation material”; not every slide will be lectured in Computer Laboratory detail. University of Cambridge I There are various code examples (particularly for 2016–2017 (Easter Term) JavaScript and Java applets) on the ‘materials’ tab of the course web page. I One exam question. www.cl.cam.ac.uk/teaching/1617/ConceptsPL/ I The syllabus and course has changed somewhat from that of 2015/16. I would be grateful for comments on any remaining ‘rough edges’, and for views on material which is either over- or under-represented. 1Acknowledgement: various slides are based on Marcelo Fiore’s 2013/14 course. Alan Mycroft Concepts in Programming Languages 1 / 237 Alan Mycroft Concepts in Programming Languages 2 / 237 Main books Context: so many programming languages I J. C. Mitchell. Concepts in programming languages. Cambridge University Press, 2003. Peter J. Landin: “The Next 700 Programming Languages”, I T.W. Pratt and M. V.Zelkowitz. Programming Languages: CACM (published in 1966!). Design and implementation (3RD EDITION). Some programming-language ‘family trees’ (too big for slide): Prentice Hall, 1999. http://www.oreilly.com/go/languageposter http://www.levenez.com/lang/ ? M. L. Scott. Programming language pragmatics http://rigaux.org/language-study/diagram.html (4TH EDITION). http://www.rackspace.com/blog/ Elsevier, 2016. infographic-evolution-of-computer-languages/ I R. Harper. Practical Foundations for Programming Plan of this course: pick out interesting programming-language Languages. -
Java Terms/Concepts You Should Know from OOPDA Glossary Terms
Java Terms/Concepts You Should Know from OOPDA A abstract class A class with the abstract reserved word in its header. Abstract classes are distinguished by the fact that you may not directly construct objects from them using the new operator. An abstract class may have zero or more abstract methods. abstract method A method with the abstract reserved word in its header. An abstract method has no method body. Methods defined in an interface are always abstract. The body of an abstract method must be defined in a sub class of an abstract class, or the body of a class implementing an interface. Abstract Windowing Toolkit The Abstract Windowing Toolkit (AWT) provides a collection of classes that simplify the creation of applications with graphical user interfaces. These are to be found in the java.awt packages. Included are classes for windows, frames, buttons, menus, text areas, and so on. Related to the AWT classes are those for the Swing packages. aggregation A relationship in which an object contains one or more other subordinate objects as part of its state. The subordinate objects typically have no independent existence separate from their containing object. When the containing object has no further useful existence, neither do the subordinate objects. For instance, a gas station object might contain several pump objects. These pumps will only exist as long as the station does. Aggregation is also referred to as the has-a relationship, to distinguish it from the is-a relationship, which refers to inheritance. anonymous class A class created without a class name. -
Scala by Example (2009)
Scala By Example DRAFT January 13, 2009 Martin Odersky PROGRAMMING METHODS LABORATORY EPFL SWITZERLAND Contents 1 Introduction1 2 A First Example3 3 Programming with Actors and Messages7 4 Expressions and Simple Functions 11 4.1 Expressions And Simple Functions...................... 11 4.2 Parameters.................................... 12 4.3 Conditional Expressions............................ 15 4.4 Example: Square Roots by Newton’s Method................ 15 4.5 Nested Functions................................ 16 4.6 Tail Recursion.................................. 18 5 First-Class Functions 21 5.1 Anonymous Functions............................. 22 5.2 Currying..................................... 23 5.3 Example: Finding Fixed Points of Functions................ 25 5.4 Summary..................................... 28 5.5 Language Elements Seen So Far....................... 28 6 Classes and Objects 31 7 Case Classes and Pattern Matching 43 7.1 Case Classes and Case Objects........................ 46 7.2 Pattern Matching................................ 47 8 Generic Types and Methods 51 8.1 Type Parameter Bounds............................ 53 8.2 Variance Annotations.............................. 56 iv CONTENTS 8.3 Lower Bounds.................................. 58 8.4 Least Types.................................... 58 8.5 Tuples....................................... 60 8.6 Functions.................................... 61 9 Lists 63 9.1 Using Lists.................................... 63 9.2 Definition of class List I: First Order Methods.............. -
Lambda Expressions
Back to Basics Lambda Expressions Barbara Geller & Ansel Sermersheim CppCon September 2020 Introduction ● Prologue ● History ● Function Pointer ● Function Object ● Definition of a Lambda Expression ● Capture Clause ● Generalized Capture ● This ● Full Syntax as of C++20 ● What is the Big Deal ● Generic Lambda 2 Prologue ● Credentials ○ every library and application is open source ○ development using cutting edge C++ technology ○ source code hosted on github ○ prebuilt binaries are available on our download site ○ all documentation is generated by DoxyPress ○ youtube channel with over 50 videos ○ frequent speakers at multiple conferences ■ CppCon, CppNow, emBO++, MeetingC++, code::dive ○ numerous presentations for C++ user groups ■ United States, Germany, Netherlands, England 3 Prologue ● Maintainers and Co-Founders ○ CopperSpice ■ cross platform C++ libraries ○ DoxyPress ■ documentation generator for C++ and other languages ○ CsString ■ support for UTF-8 and UTF-16, extensible to other encodings ○ CsSignal ■ thread aware signal / slot library ○ CsLibGuarded ■ library for managing access to data shared between threads 4 Lambda Expressions ● History ○ lambda calculus is a branch of mathematics ■ introduced in the 1930’s to prove if “something” can be solved ■ used to construct a model where all functions are anonymous ■ some of the first items lambda calculus was used to address ● if a sequence of steps can be defined which solves a problem, then can a program be written which implements the steps ○ yes, always ● can any computer hardware -
Intel ® Fortran Programmer's Reference
® Intel Fortran Programmer’s Reference Copyright © 1996-2003 Intel Corporation All Rights Reserved Issued in U.S.A. Version Number: FWL-710-02 World Wide Web: http://developer.intel.com Information in this document is provided in connection with Intel products. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document. EXCEPT AS PROVIDED IN INTEL’S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS, INTEL ASSUMES NO LIABILITY WHATSO- EVER, AND INTEL DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY, RELATING TO SALE AND/OR USE OF INTEL PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PAR- TICULAR PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. Intel products are not intended for use in medical, life saving, or life sustaining applications. This Intel® Fortran Programmer’s Reference as well as the software described in it is furnished under license and may only be used or copied in accordance with the terms of the license. The information in this manual is furnished for infor- mational use only, is subject to change without notice, and should not be construed as a commitment by Intel Corpora- tion. Intel Corporation assumes no responsibility or liability for any errors or inaccuracies that may appear in this document or any software that may be provided in association with this document. Designers must not rely on the absence or characteristics of any features or instructions marked "reserved" or "unde- fined." Intel reserves these for future definition and shall have no responsibility whatsoever for conflicts or incompatibil- ities arising from future changes to them. -
Software II: Principles of Programming Languages Control Statements
Software II: Principles of Programming Languages Lecture 8 – Statement-Level Control Structures Control Statements: Evolution • FORTRAN I control statements were based directly on IBM 704 hardware • Much research and argument in the 1960s about the issue – One important result: It was proven that all algorithms represented by flowcharts can be coded with only two-way selection and pretest logical loops Control Structure • A control structure is a control statement and the statements whose execution it controls • Design question – Should a control structure have multiple entries? Selection Statements • A selection statement provides the means of choosing between two or more paths of execution • Two general categories: – Two-way selectors – Multiple-way selectors Two-Way Selection Statements • General form: if control_expression then clause else clause • Design Issues: – What is the form and type of the control expression? – How are the then and else clauses specified? – How should the meaning of nested selectors be specified? The Control Expression • If the then reserved word or some other syntactic marker is not used to introduce the then clause, the control expression is placed in parentheses • In C89, C99, Python, and C++, the control expression can be arithmetic • In most other languages, the control expression must be Boolean Clause Form • In many contemporary languages, the then and else clauses can be single statements or compound statements • In Perl, all clauses must be delimited by braces (they must be compound) • In Fortran -
Chapter 15. Javascript 4: Objects and Arrays
Chapter 15. JavaScript 4: Objects and Arrays Table of Contents Objectives .............................................................................................................................................. 2 15.1 Introduction .............................................................................................................................. 2 15.2 Arrays ....................................................................................................................................... 2 15.2.1 Introduction to arrays ..................................................................................................... 2 15.2.2 Indexing of array elements ............................................................................................ 3 15.2.3 Creating arrays and assigning values to their elements ................................................. 3 15.2.4 Creating and initialising arrays in a single statement ..................................................... 4 15.2.5 Displaying the contents of arrays ................................................................................. 4 15.2.6 Array length ................................................................................................................... 4 15.2.7 Types of values in array elements .................................................................................. 6 15.2.8 Strings are NOT arrays .................................................................................................. 7 15.2.9 Variables — primitive