CMPT 102 Introduction to Scientific Computer Programming

1 © Janice Regan, CMPT 102, Sept. 2006

CMPT 102Introduction to Scientific Computer Programming

Course Organization

© Janice Regan, CMPT 102, Sept. 2006 2

CMPT 102: Introduction to Scientific Computer Programming

Monday, Wednesday, Friday 9:30-10:20 Textbook:

C Program Design for EngineersAuthors: Jeri R. Hanly, Elliot B. Koffman

Additional References: Engineering Problem Solving with C, 3rd edition

Author: Delores M. Etter The C Programming Language

Authors: B. W. Kernighan, D. M. Ritchie


Class web-site All the information discussed today and more

can always be found on the class web-site To find the class web site go to

http://www.cs.sfu.ca/CourseCentral Select Course Home pages Select the Homepage for CMPT 102

Course Central is also a useful link to abundant information useful to students taking a computing science course


http://www.cs.sfu.ca/CourseCentral


Course selection page

Click here to go

to CMPT102 website


CMPT 102 Website


My availability


Exams Dates, Course Evaluation


Exams and Evaluation


Evaluation Assignments: 30% Weekly Quizzes: 15%

No quiz in week of midterm, week of Thanksgiving or week of Remembrance day

Lab Problems: 5% Practice Problems: no credit Midterm Examination: 15% Final Examination: 35%


Assignments Four assignments

Each assignment worth 7.5% of your course grade

Assignments are to be completed individually Problems similar to the assignments will

appear on the midterm and the final. Help is available during weekly lab hours Complete solutions will be posted


Lab Problems Four short lab problems Each lab problem is worth 1.25% of your final grade Practice Problems: no credit BUT valuable experience that will be useful when

completing lab problems and assignments

There are no Labs in the first week of classes (Sept. 5-8) Lab hours are not held on statutory holidays (Thanksgiving and Remembrance Day)

Weekly Quizzes: 15% One question on material covered in labs Monday-Tuesday of the same week Each quiz marked out of 17, worth 1.7% of the final grade All quiz results will be included in your final grade

Midterm: 15% Final: 35%


Quizzes During each Wednesday’s lecture, you will be

asked to answer one question based on material covered in the lab exercises that week.

You will be asked to write a short concise paragraph of 10-15 sentences, explaining a concept or method, or a short piece of code.

You will be given 10-15 minutes to answer. Your answer will be graded out of 17 (each quiz is

worth 1.7% of your final grade)


Midterm and Final One 50 minute in class midterm One 3 hour final examination 35% short answer problems 65% longer problems that utilize several

important concepts and require integration of those concepts.

A sample exam, including solutions, will be posted two weeks before the midterm and two weeks before the final exam


Assignments, Labs, Solutions


Important Dates


Assignments At least two weeks before the due date the

assignment will be posted on the website Assignments must be completed individually Assignments will require you to combine and use

many concepts and tools you have learned Assignments will be much more demanding than lab

problems or practice problems Complete solutions to all assignments will be posted Information of proper preparation of assignments and

lab problems is available on the class website.


Labs On or before Friday of each week problems will

be posted for the next week. These problems will be identified as Lab Problems: To be completed individually or in a

small group (up to four students) Submitted for grading

Practice Problems: A chance to use a new idea in a simple application, before you need to integrate multiple ideas into assignments. Collaboration is encouraged Not submitted for grading

Complete solutions to all problems will be posted


Grading Information Assignments and Lab Problems should be:

submitted electronically using the submission server submitted in hard copy to the 102 drop box

Bonus points (10%) are available for submitting assignments more than 72 hours early

No late assignments or lab problems will be accepted

Unofficial grades will be available on GradeBook Login: your SFU computer ID, your student number

as password. Find link on Course Central


Where to submit assignments: 1


Where to submit assignments: 2

Submission drop boxes


Required Readings, Notes


Readings and Notes


Academic Honesty


Academic HonestyRead the

policy


Getting Started If you have not already done so activate

your SFU computing account (CCN, Campus Computing Network account.) Use your own machine at home, or go to the

assignment lab (AQ 3145) Email regarding the class will be sent to your

Campus Account, so check it regularly Steps to activate your account …


Activating your CCN account (1)

Select mySFU


Activating your CCN Account (2)

Select Apply for ID, the follow the instructions. You will need your student ID and your TeleReg PIN


Computing Science Instructional Labs (CSIL) The CSIL LINUX lab is available for your use at

all times beginning in the second week of classes. (ASB 9838)

At particular times the instructor and/or TA will be available in the lab to answer your questions. Instructor: Mon. 1:30-3:00 PM,

Tue: 9:00-10:30 AM TA: Tue: 10:00 – 10:30 AM . TBA


Finding CSIL labs: 1


Finding CSIL labs: 2

CSIL Labs


Access to CSIL CSIL is protected by a security card

access system As a student in a computing science course

you are eligible to have a security access card for CSIL

If you are pre-registered your access card may be picked up from the card office at traffic and security (there is a $15 refundable deposit and a $3 processing fee)


CSIL Rules Before you can use any of the computers in the

CSIL you must sign and return an ethics form. By signing the ethics form you indicate that you have

read and agree to abide by the SFU and CSIL regulations regarding use of computing resources and computer labs.

Links to these policies can be found on the class website or on Course Central

You can return your ethics forms during next class, or directly to the computing science main office.


http://www.cs.sfu.ca/CourseCentral

Select to reach Policies


CSIL page

IMPORTANTRead thePoliciesBefore Signing

Your Ethics form


Getting Started in CSIL Before you try programming in CSIL read

the information provided for you Read the general information pages Browse the FAQs, Now you are ready to start

Your CSIL computer ID and password and the ID an password you use for your SFU email account.


CSIL page

Read thegeneral

information

Browse The

FAQs


Labs and using CSIL The computers in CSIL are available 24/7 At some times your instructor or TA will be

available to answer questions At some times OPEN LAB TA’s will be

available to answer questions. A list of TA’s presently in the lab will be

posted on the white board in CSIL.


Optional Lab Hours Attendance at optional Lab hours is strongly

encouraged Lab Hours are held in the LINUX area of CSIL labs Lab Hours provide an opportunity to work with others

sharing knowledge and experience. Lab Hours give you an opportunity to ask the

instructor or TA one on one questions about problems and assignments.

Lab Hours help you learn the required concepts one by one and allow you to ask questions to assure you understand each one.


Operating System In the CSIL labs you will be using

computers that run the LINUX operating system

In the first optional lab hours there will be tutorials on how to use the LINUX operating system (1 per hour)

The tutorial will also be posted so you can try it yourself at another time


Reading Assignment Visit and read the information on the class

website Be sure you can find

Posted notes Reading assignments for each lecture Assignment due dates Instructions on using the CSIL labs Instructions on using your own computer for

assignments Have any questions ready for next lecture

42 © Janice Regan, CMPT 102, Sept. 2006

CMPT 102Introduction to Scientific Computer Programming

Chapter 1: Computer Components


Hardware and Software A computer is a machine designed to perform

operations specified with a set of instructions called a program.

Hardware refers to the computer equipment. keyboard, mouse, terminal, hard disk, printer, CPA

Software refers to the programs that describe the steps we want the computer to perform.


CPU

Computer Hardware CPU –

Central processing unit

ALU – Arithmetic and logic unit

ROM – Read only memory

RAM – Random access memory

InternalMemory

ExternalMemory

Input OutputProcessor

ALU

Cache/Memory


Software: Operating System A system of computer programs that control the

interaction of the user and the computer hardware. Examples: Linux, Windows, QNX,…

Purposes of the operating system Controls communication between input and output

hardware and each process running in the computer. Directs and orders all operations of the computer Allocates and shares resources (memory,processor…) Controls access to resources and data (security) Provides a user interface (UI) and/or graphical user

interface (GUI) Stores and accesses data and applications


Example: Command Line UI Windows Command Prompt


Example: Graphical UI (GUI) Windows explorer


Computer Software: Applications

Application Software (Software Tools) Word processors (Microsoft Word, WordPerfect, ...) Spreadsheet programs (Excel, Lotus1-2-3, ...) Computer games Communication software (email, chat, web

browser…) Telecommunication software (VOIP, …)


Computer Software: Languages Some Computer Languages

Machine language (machine instruction set) assembly language high level languages

C, C++, Ada, Fortran, Basic, Java Do YOU know of any others? mathematical computation tools (MATLAB,

Mathematica, ...) Application software is written using computer

languages.


Machine language Each type of processor (like Pentium 4, Athalon,

Z80, …) has its own instruction set Each instruction in an instruction set does a

single thing like access a piece of data, add two pieces of data, compare two pieces of data …

Each instruction is represented by a unique number This # may be different for different instruction sets, but no two instructions in the same instruction set will have the same #


Machine Language programs In machine language a program is a list of

instructions Each instruction is represented by a number Inside the memory of the computer each

number is represented in binary (as a constant length string of 1’s and 0’s)

The long string of 0’s and 1’s is easy for the computer to understand and very difficult for a Human to read or write


Assembler Assembler languages make it easier for

the programmer. Assembler is easier for humans to read/write The numbers that identify each of the

instructions in the instruction set are replaced with mnemonics like ADD, CMP, …

The code, written using these mnemonics is written into a text file.


Assembler Programs The code for an Assembler program is written

into a text file. The computer read 1’s and 0’s not text How do we translate to machine readable form?

A computer program called a compiler is used to translate the text file (called a source file) containing the assembler code into machine readable code

The compiler writes a binary file containing the machine readable code (called an object file)


Programs in High Level Languages Assembler is easier to read/write than machine

language. It is still very cumbersome High level languages are easier to write than

assembler The compiler is more complex, but that is a tool you

use, not one you write In this course we will learn the language C The rest of today's discussion is equally

applicable to C or to any other compiled language (C++, Fortran, …)


Writing your program

Editor, Type inyour program

Source File

Text saved on hard disk

CompilerTranslate text into

Machine Readable code


Source files Contains the text you type into a text editor The text is a program The program is a list of instructions written in a

special Human readable language (C) The program can be translated, from the Human

readable language (in source file) to a machine readable language (in object file), by a compiler

A compiler is a special piece of software used to translate from source files to object files


Source files Source File:

Write using a text editor like Kate Do not write your code using a word

processor like Microsoft Word. A word processor will save in a special format.

The compiler reads only text, not special formats.

Beware: your text does not differentiate between a word processor and an editor


Perfect Code? Finding Errors 1 It is highly unlikely than any of us will always

write perfect code that contains no errors How do we find errors? Are there different kinds of errors? Yes A computer program can contain syntax errors.

semantic errors, or logical errors When and how can we detect and correct

errors? Compile errors Link errors Run Time Errors


Syntax Errors A computer program can contain syntax errors A computer language follows simple rules

how words and punctuation of different types may be combined.

In English syntax is similar to grammatical structure The compiler for a high level language can

detect errors that break those simple of syntax (syntax errors)

Syntax Errors are usually detected at compile time


Semantic Errors A computer program can contain semantic

errors Semantics relates to the meaning of the words

in a sentence or a computer language command Just like a grammatically correct English

sentence can be nonsense, a syntactically correct high level computer language command can also contain semantic errors

Some semantic errors may be found by the compiler, some will be found when the program is linked, some may be found at run time


Logical Errors When your program completes but gives

an unexpected answer it usually means there is a error in the logic in your solution of the problem

Logic errors can also cause a program to fail part way through execution


Writing your programEditor, Type inyour programSource File

CompilerTranslation toMachine code

Syntax or Semantic Errors, Compiler Generates error Messages. To help us find and Correct errors in the

Source File

Object File

Binary, machine readable file

Syntactically Correct

code

Code with

syntax

Or semantic

errors

Editor, CorrectSyntax Errors


Perfect Code? Finding Errors 2 If your code contains compile time errors is it

correct? NOT NECESSARILY How do we find the remaining errors? Use a tool that does more checks than the

compiler (splint). Move on to linking the code to libraries etc.

The linker resolves references, words in your program than are defined elsewhere

Errors occur when the definitions cannot be found Errors occur when the use of the word does not

correspond to the definition


Linking your programEditor, Enter

program

Source File

(Text)

Compile

Find Syntax and

SemanticErrors

Object File

(binary)

CorrectErrors

LinkerResolves

References among

object files

Other Object FilesLibraries …

Executable File(load module)

(binary)

Semantic Errors Reported: Finds words with no defined meaning.

Code has linker errors


Perfect Code? Finding Errors 3 If your code compiles and contains no

errors that can be found by the linker (or splint) is it correct? NOT NECESSARILY

How do we find the remaining logic and semantic errors?

When you run your executable program it may not complete (may or may not

generate error message) It may complete and give the wrong answer


Loading/Running your programEditor, Enter

program

Source File

(Text)

Compile

Find Syntax and some

SemanticErrors

Object File

(binary)

CorrectErrors

LinkerResolves

References Other

Object FilesExecutable File

(binary)

Link Errors Reported:

LoaderCopies

ExecutableAnd Runs

Input data

output resultsCPU


Summary:Executing a Computer Program

Compiler Converts a source file (containing your human

readable program in C) to and object file (computer readable binary file)

Linker Converts object program to executable program

Compile Link/load ExecuteC languageProgram inText file(source file)

MachinelanguageProgram In binary file(object file)

Program output

Input data

Otherobject files


Summary: Types of Errors Syntax errors

Errors in syntax, how words are combined and used reported by the compiler or splint

Semantic errors Errors in the meaning of words,

Reported by the linker (linker errors) Reported by the compiler (compile time errors) Found at execution time (run-time errors)

Logic errors Errors causing the incorrect results, not reported Errors causing program failure (run-time errors)

Documents

CMPT 102 Introduction to Scientific Computer Programming