Programming. Introduction to the course

Transcription

1 Programming Introduction to the course

2 Motivation 2

3 What is Programming? } Some definitions: } Telling a very fast moron exactly what to do } A plan for solving a problem on a computer } The process of developing and implementing various sets of instructions to enable a computer to do a certain task } Specifying the structure and behavior of a program } Testing that the program performs its task correctly according to some criteria! 3

4 Why Programming is Hard? } Ambition for the computer to do complex things } Computers are nitpicking, unforgiving and dumb beasts } The problems are more challenging that we d thought } So we don t always know the implications of what we want } To program is necessary to understand the problem } When you program, you spend significant time trying to understand the task you want to automate } Programming is part practical, part theory } Only practical knowledge will leave you with very hard issues to solve (e.g. how to sort values?) } Only theory knowledge doesn t solve anything 4

5 Why You Must Learn to Program? } Our civilization runs on software } Most engineering activities involve software } Many software does not run on PCs! } Much more than games, word processing, browsing, and spreadsheets! } Phones } Consoles } Cameras } Drones } MP3/DVD players } Routers } Televisions } Fridges } Toasters ;-) } Etc.. 5

6 Ships, Planes, Phones, etc 6

7 Course Aims } Practical programming using the C language } For beginners } Who desire to become professionals } i.e., to produce software systems that users will use } Who are assumed to be bright } Though not (necessarily) geniuses } Who are willing to work hard } Though do need to sleep occasionally 7

8 Key Objectives } Students must learn: } Fundamental programming concepts and methodologies } Some basic algorithms and data structures } Basic standard C language } After this course, you must be able to: } Write small/medium C programs } Understand much larger and complex programs } Learn the foundations of many other languages by yourself } Proceed with an advanced programming course (e.g. C++) } After this course, you will not be able: } To be an expert programmer } Or an expert user of advanced libraries 8

9 Pre-Requisites } None!!!!!!!! } For real, just some minimum concepts of computer science } File editing } Willingness to learn } Hard work 9

10 Course Professors } João Ascenso } Theory, labs and practical classes } joao.ascenso@tecnico.ulisboa.pt } } Instituto de Telecomunicações (Torre Norte) - Sala } Internal extension:

11 Course Professors } Nuno Horta } Problems and labs } nuno.horta@lx.it.pt } } Instituto de Telecomunicações (Torre Norte) 11

12 Course Professors } Bertinho Costa } Problems } bac@comp.ist.utl.pt } } INESC-ID } Internal extension:

13 Course Webpage: Fenix } Information about the course } Evaluation } Course description } Assignments } Schedule } News } Software } Textbooks } Grades } Etc.. 13

14 Theory Classes } Exposition to the course topics } Active learning approach } Indispensable } Assiduity (avoid at all cost skipping classes) } Self-study and experimentation } 1.0 hour before/after each class } Read the corresponding book chapter 14

15 Problems Classes } Concept, design and implementation of programs } Without computer (exception: 1 st class)!!!! } Writing in paper :P } Every two weeks } Registration is already performed } Advance preparation is necessary!!! } 1.5 hours before each class } Print the problem set } Careful reading of each problem } Solve each problem before 15

16 Laboratory Classes } Groups of 2 students } Solve practical exercises in the computer } Essential to prepare! } 1.5 hours before the class } Print, read and solve each of the exercises } 0.25 pts max by successfully solving one of the exercises } Specified by the professor at the beginning of each lab class! } Bi-weekly schedule } Registration must be made in FENIX } Starting at 17h30 of Monday (20 th of February) 16

17 General Help } Regular extra classes to help students } Schedule to be announced in the course webpage } Free access to all students } Best way to solve any doubts or get some help in debugging your programs } Other possibility } Send an to the professor } Write clear, concise and short s 17

18 Basic Rules } Attend each class! } Study the corresponding course materials } Before class!!! } Feedback is welcomed! } Prepare the labs } Program for real! } Read programs written by others 18

19 Rough Course Outline (1) } Introduction to programming } Algorithms, languages, syntax and semantics, flowcharts } Basic concepts } Program structure, comments, constants, variables, data types } Operators, expressions, console I/O } Flow control statements } Repetition statements } Functions and procedures } Declaration, invocation, scopes, function result, passing by value/reference } Strings } Reading and processing } File I/O, I/O streams } Opening and closing files 19

20 Rough Course Outline (2) } Arrays(vectors) } Declaration, indexing, data access and pointers } Multidimensional vectors and dynamic allocation } Pointers vs. arrays: different forms of the same phenomenon } Graphical user interfaces } Data structures } Declaring, using and initializing structures } Pointers to structures and arrays of structures } Data abstraction } Multiple files, #includes, libraries } Dynamic data types } Declaration, memory allocation, access } Stack, push and pop operations } List, insert and remove operations 20

21 Planning Week Date Problems Labs Plan Notes 1 19-Feb Course Presentation, Concepts 2 26-Feb X Concepts, Control flow 3 05-Mar X Loops, Functions 4 12-Mar X File I/O, Arrays 5 19-Mar X Strings, SDL Apr X Multi-Arrays, First Project Help 7 09-Apr X Pointers and Dynamic Memory Intermediate Project - 15th April 8 16-Apr X Structures, Enums and Unions 9 23-Apr X Compilation, Linked Lists Apr X Linked Lists, Stacks May X Queues May X Real-World Programming Study Cases May X Final Project Help Final Project - 24th May May Oral Discussions 21

22 Evaluation } First Project P1: 15% } Should be made individually by each student } Final Project (with oral discussion) P2: 35% } Made in groups of 2 students } Lab classes: 5% } Exam E: 45% } Minimum grades: } E >= 9.5 } P2 >= 10 && (P1*0.3+P2*0.7) >

23 Recommended Bibliography } The C Programming Language - The ANSI edition } Autor(es):Brian W. Kernighan e Dennis M. Ritchie } Fundamentos de Programação } Marques de Sá } Linguagem C } Luís Damas } Apontadores e Estruturas de Dados Dinâmicas em C } Fernando Mira da Silva 23

24 Computing Facilities } Laboratories with PCs installed with Linux } } Have a personal computer (laptop) } Recommended but not essential } Install Linux } Use VirtualBox on Windows } The use of proprietary compilers is forbidden } Turbo C, Visual C,... 24

25 Programming Software Development: Concepts and Tools

26 Software Development Cycle 26

27 Programming Steps Explained } Design step: } Definition of a solution (in paper) } Requires understanding the problem and possible solution (behavior) } Abstract the implementation details } Coding step: } Implement the solution using the programming language } Requires the understanding of a programming language } Syntax and semantic } May require the understanding of well-known methods to solve one or more steps } Compiling step: } Translates the high-level language (understood by us) to a low-level language (understood by the computer) } May lead to the discovery of syntax errors 27

28 Debugging } Discovery of the program bugs } Execute } Test } Inspect source code } Correct 28

29 Introduction to the C Language } Developed in the 1970s in conjunction with development of UNIX operating system } When writing an OS kernel, efficiency was crucial } UNIX originally written in low-level assembly language but there were problems: } No structured programming (e.g. encapsulating routines as functions, methods, etc.) code hard to maintain } Code worked only for particular hardware not portable } C takes a middle path between low-level assembly language } Direct access to memory layout through pointer manipulation } Concise syntax, small set of keywords } and a high-level programming language like Java 29

30 Standard C } Standardized in 1989 by ANSI (American National Standards Institute) known as ANSI C } International standard (ISO) in 1990 which was adopted by ANSI and is known as C89 } As part of the normal evolution process the standard was updated in 1995 (C95) and 1999 (C99) } C++ and C } C++ extends C to include support for Object Oriented Programming and other features that facilitate large software development projects } C is not strictly a subset of C++, but it is possible to write Clean C that conforms to both the C++ and C standards.

31 Compilation and Linking } C source code is first written by you (human readable) } Compiler translates what you wrote into object code } Simple enough for a computer to understand } Linker connects your code to some system code } Examples: input/output libraries, operating system code, etc. } A executable program is obtained } An.exe file on windows or an a.out file on Unix 31

32 Separate Compilation } A C program consists of source code in one or more files } Each source file is run through the preprocessor and compiler, resulting in a file containing object code } Object files are tied together by the linker to form a single executable program Source code file1.c Source code file2.c Preprocessor/ Compiler Preprocessor/ Compiler Object code file1.o Object code file2.o 32 Libraries Linker Executable code a.out

33 Separate Compilation } When a program is modified, a programmer only edits a few lines of source code each time } With separate compilation, only the files that have been changed since the last compilation need to be recompiled } For very large programs, this can save a lot of time 33

34 Preprocessor } The preprocessor receives source code and according to certain directives change it before compilation } Directive: a line of source code starting with the # symbol } The preprocessor works in a very crude way, simply cutting and pasting does not really know anything about C! Your source code Enhanced and obfuscated source code Object code Preprocessor Compiler 34

35 Programming End