Lecture 19 / Chapter 13 COSC1300/ITSC 1401/BCIS 1405 12/5/2004 Lecture 19 / Chapter 13 COSC1300/ITSC 1401/BCIS 1405 12/5/2004 General Items: Computer Program • Lab? Ok? • Read the extra credits • A series of instructions that direct a computer to perform tasks • Need to come to class • Such as? Who is the programmer? • Have a quiz / no books / use notes -> What is the big idea • School is almost over • Programming language is a series of rules for writing the instructions • • There are hundreds of computer programs – need-based! Reading Materials: Programming language • - Two basic types: Low- and high-level programming languages Miscellaneous: o Low-level: Programming language that is machine-dependent ° Must be run on specific machines o High-level: Language that is machine-independent ° Can be run on different types of machines Programming Language Low Level High Level Machine Assembly Language Language Procedural Nonprocedural Remember: Ultimately, everything must be converted to the machine language! Object Oriented F.Farahmand 1 / 12 File: lec14chap13f04.doc F.Farahmand 2 / 12 File: lec14chap13f04.doc Lecture 19 / Chapter 13 COSC1300/ITSC 1401/BCIS 1405 12/5/2004 Lecture 19 / Chapter 13 COSC1300/ITSC 1401/BCIS 1405 12/5/2004 Categories of programming languages o Nonprocedural language -> Programmer specifies only what the - Machine language program should accomplish; it does not explain how o Only language computer understands directly - Forth-generation language - Assembly language o Syntax is closer to human language than that of a 3GL o Instructions made up of symbolic instruction codes o SQL and report generator are examples o Assembler converts the source code to the machine language - Fifth-generation language - Third-generation language o Provides visual or graphical interface for creating source code o Uses a series of English-like words to write instructions o Visual Basic.NET is an example - Procedural language -> Programming instructions to tell computer what - Common procedural programming languages to accomplish and how to do it o BASIC o Compiler: ° Designed for use as a simple, interactive problem-solving ° Separate program that generates programming list (consists of language errors) ° Beginner's All-purpose Symbolic Instruction Code ° Program that converts entire source program into machine o COBOL language before executing it o C (Changed B to C!) o Object program ° Used for execution later o Interpreter ° Program that translates and executes one program code statement at a time ° Does not produce an object Source Compiler Object Code: Program Assembly/3 ° F.Farahmand 3 / 12 File: lec14chap13f04.doc F.Farahmand 4 / 12 File: lec14chap13f04.doc Lecture 19 / Chapter 13 COSC1300/ITSC 1401/BCIS 1405 12/5/2004 Lecture 19 / Chapter 13 COSC1300/ITSC 1401/BCIS 1405 12/5/2004 Object-oriented (OO) approach o The structured programming does not explain how to keep the data and program together o Eliminates redundant programming o No more spaghetti code o Programmer can package data and program (or procedure) into a single unit, called an object (uses the OO approach) o OOP is event-driven o Checks for and responds to set of events o C++ is a complete object-oriented language OO Programming languages Hundreds of programming languages exist – They are different in flexibility, user interface, and functionality o C++ : Classes and events o Java and Java applets: Small Java program that runs inside another program such as a Web browser o Visual Programming Language ° Windows-based application that assists programmers in developing event-driven Windows-based applications ° Fifth – generation language • Allows drop and drag of objects • Easy to use ° Examples: • Visual Basic • Visual Studio/Visual C++/Visual C# .NET o Run over the Internet o Easier programming development o Suitable for large/small – scale applications F.Farahmand 5 / 12 File: lec14chap13f04.doc F.Farahmand 6 / 12 File: lec14chap13f04.doc Lecture 19 / Chapter 13 COSC1300/ITSC 1401/BCIS 1405 12/5/2004 Lecture 19 / Chapter 13 COSC1300/ITSC 1401/BCIS 1405 12/5/2004 Web page program development tools o Common Gateway Interface Program (CGI) o Tools used to create web pages ° Used for sending and receiving information over the web o Adding special effects and forms to a Web page ° Basic Idea: ° Examples: Cookies, Shopping cards, Games, and many other • Resides in the server multimedia effects • When a search is requested the it is sent to the CGI ° Script: Interpreted program that runs on client program ° Applet: Also usually runs on client, but is compiled – runs • The CGI contacts the database and requests the faster than script information ° Servlet: Applet that runs on server • The CGI receives the information from the database and ° ActiveX control: Small program that runs on client shows it in HTML format and it is sent to the web o HTML browser ° Hypertext Markup Language – set of special codes used to create web page- ° Not a programming language – Page formatting language ° Uses tags an must be kept as an ASCII file o Dynamic HTML: ° Allows you to include more graphics and interactivity on Web page (pointing to a text changes the shape) ° Animations, Interactions, Scroll bar, pop-up windows o XML: eXtensible Markup Language ° Allows Web page developers to create tags that describe data passed to a client so client, rather than server, can process data – different platforms can display the same XML o XHTML: eXtensible HTML Includes features of HTML and XML o WML Wireless Markup Language ° Allows Web page developers to design pages specifically for micro-browsers ° Uses the wireless application protocol (WAP) o Web page authoring: ° Dreamweaver MX, FrontPage, Flash F.Farahmand 7 / 12 File: lec14chap13f04.doc F.Farahmand 8 / 12 File: lec14chap13f04.doc Lecture 19 / Chapter 13 COSC1300/ITSC 1401/BCIS 1405 12/5/2004 Lecture 19 / Chapter 13 COSC1300/ITSC 1401/BCIS 1405 12/5/2004 System development life cycle Program development life cycle - A system is a set of components that interact to achieve a common goal - A computer program is a set of instructions that directs computer to - System development life cycle generally has 5 phases: perform tasks o Planning - A programming language is a set of words, symbols, and codes that o Analysis enables a programmer to communicate instructions to a computer o Design - PDLC is a steps followed to build computer programs o Implementation o Analyze problem o Support ° Review program specifications package ° Meet with systems analyst and users ° Identify each program’s input, output, and processing components o Design problems ° Grouping program activities to modules (top-down design) ° Providing a solution algorithm for each phase and testing it (structured design) ° Top-down design: Focuses on what program should do ° Structured design: Focuses on how to build program based on requirements (Creating a hierarchical chart) • Uses a technique that builds all program logic by combining three control structures: o Sequence control structure (Input, Process, Output) o Section control structure (if-then-else) o Repetition control structure (do-while) ° Writing proper programs: • No-dead codes • No infinite loops • One entry point • One exist point (no spaghetti code – not structured) ° Using design tools (graphical or written description of each module) F.Farahmand 9 / 12 File: lec14chap13f04.doc F.Farahmand 10 / 12 File: lec14chap13f04.doc Lecture 19 / Chapter 13 COSC1300/ITSC 1401/BCIS 1405 12/5/2004 Lecture 19 / Chapter 13 COSC1300/ITSC 1401/BCIS 1405 12/5/2004 • Flowchart (Graphically shows logic in a solution QUIZ algorithm) • Pseudocode (Uses condensed form of English to convey What is a computer program? program logic) o Code programs ° Translating solution algorithm into a programming language Why do we use Object-oriented programming language? ° Entering programming language code into the computer o Test programs ° Goal is to ensure program runs correctly and is error free - Three types of errors Name 3 programming languages. • Syntax • Logic • Run time ° Debugging: Process of locating and correcting syntax and logic Name 2 web page development techniques. errors in program o Formalize solution ° Programmer performs two activities What is HTML? • Reviews program code • Reviews documentation o Maintain program ° Identify errors ° Identify enhancements ° Involves modifying existing programs to improve their functionality F.Farahmand 11 / 12 File: lec14chap13f04.doc F.Farahmand 12 / 12 File: lec14chap13f04.doc .