CS-2301 System Programming for Non-Majors

1. CS-2301 System Programming for Non-Majors Professor Hugh C. LauerD-term 2009 (Slides include materials from The C Programming Language, 2nd edition, by Kernighan and Ritchie and from C: How to Program, 5th and 6th editions, by Deitel and Deitel) Introduction

2. Course Objectives C language programming Designing, implementing, debugging, etc. How the hardware executes C programs … and other kinds of programs Preparation for computational challenges of engineering, scientific, and other professions Preparation for upper-level courses in computing “Thinking computationally” Introduction

3. Why? Computing and Programming: a life skill for all technical professionals Thinking Computationally: organizing your engineering/scientific/technical thoughts to be amenable to computational solutions Introduction

4. Why C? Because we have to! Many situations outside of CS where it is only language or system available Small, embedded systems, instrumentation, etc. Many “low-level” situations that don’t have support for “high-level” languages Operating systems, real-time systems, drivers Introduction

5. Why not C? C is very low-level Data structures must be programmed “by hand” Operations must be done out in “long hand” No support for “object oriented” design Marginal support for higher-level thought processes Better alternatives available for technical applications Verilog, VHDL, System C– semiconductor design Matlab, SimuLink – physical modeling LabView – instrumentation and control Excel – accounting and statistics SQL – billing and transactions … Introduction

6. This Course • Lectures • C programming language, syntax, semantics, etc. • Common data structures that technical professionals are likely to need or encounter in C • Programming Assignments • Write programs to exercise various language constructs and data structures • Mandatory for passing this course • Lab Sessions • How to use the system, tools, debuggers, etc. • Practical help from TAs, etc. Introduction

7. This Course (continued) Tuesdays & Fridays, 8:00–9:50 AM Fuller 320 Weekly Lab Sessions D01 – Kaven 202, Wednesdays 2:00-2:50 PM D02 – Kaven 202, Wednesdays 3:00-3:50 PM D03 – Kaven 202, Wednesdays 4:00-4:50 PM Three exams (one hour each) April 3 April 17 May 5 Review session prior to exam on same day Closed book, one 8½-by-11 sheet of prepared notes, no calculators or electronics Introduction

8. Prerequisites CS-1101 or CS-1102 Or other “first” programming course Or programming job, or other experience Background survey Note: credit may not be earned for both CS-2301 and CS-2303 Introduction

9. Logistics Course web site http://www.cs.wpi.edu/~cs2301/d09 Professor’s office Hours Tuesdays and Fridays, 10:00-11:00 AM, or by appointment(additional hours TBD) Fuller 137:– (508) 831-5493 Contacts <Professor’s last name> @ cs.wpi.edu Class e-mail lists cs2301-allor cs2301-staff @ same domain Teaching assistants Rabin Karki (TA) Jeff Zhou (TA) Brian Bates (SA) Introduction

10. Required Textbook The C Programming Language, 2nd edition, by Brian Kernighan and Dennis Ritchie, Prentice Hall, 1988 Bring to all classes and all lab sessions Introduction

11. Textbook Outline Chapter 1: a tutorial aimed at people who already know how to program Chapters 2-8: description of C language Slightly different order from Chapter 1 Appendix A: the C language reference Official definition of language is here! Appendix B: the standard libraries You will use these a lot! Introduction

12. Ground Rule #1 There are no “stupid” questions. It is a waste of your time and the class’s time to proceed when you don’t understand the basic terms. If you don’t understand it, someone else probably doesn’t it, either. Introduction

13. Ground Rule #2 Help each other! Even when a project or assignment is specified as individual, ask your friends or classmates about stuff you don’t understand. It is a waste of your time try to figure out some obscure detail on your own when there are lots of resources around. When you have the answer, write it in your own words (or own coding style). Introduction

14. Names and Faces Introduction • It is in your own interest that I know who you are. • Students who speak up in class usually get more favorable grades than those who don’t • When speaking in class, please identify yourselves

15. WPI Academic Honesty Policy It is a violation of the WPI Academic Honesty Policy to submit someone else’s work as your own. It is not a violation of WPI’s Academic Honesty Policy to ask for help! Classmates, TAs, friends, mentors, … Explanations of things you don’t understand Introduction

16. Additional Help Introduction • Academic Resource Center has Tutors available to assist in CS 2301. • The schedule is posted and copies are available on the door of the M*A*S*H room and Tutor Center, Daniels Hall, 1st floor.

17. Instructor — Hugh C. LauerAffiliated Associate Professor Ph. D. Carnegie-Mellon, 1972-73 Dissertation “Correctness in Operating Systems” Lecturer: University of Newcastle upon Tyne, UK Approximately 30 years in industry in USA Research topics Operating Systems Proofs of Correctness Computer Architecture Networks and Distributed Computing Real-time networking 3D Volume Rendering Surgical Simulation and Navigation … Introduction

18. Systems and Programming Experience IBM Corporation University of Newcastle Systems Development Corporation Xerox Corporation (Palo Alto) Software Arts, Inc. Apollo Computer Eastman Kodak Company Mitsubishi Electric Research Labs (MERL) Real-Time Visualization Founded and spun out from MERL Acquired by TeraRecon, Inc. SensAble Technologies, Inc. Dimensions Imaging, Inc. (new start-up) Introduction

19. Experience (continued) CTO, Chief Architect of VolumePro™ 1000 World’s first interactive 3D rendering engine for CT, MRI, seismic scans for PC-class computers 7.5-million gate, high-performance ASIC 109 illuminated graphical samples per second Two seminal contributions to computer science Duality hypothesis for operating systems (w/Roger Needham) First realization of opaque types in type-safe languages (with Edwin Satterthwaite) 21 US patents issued Computer architecture Software reliability Networks Computer graphics & volume rendering Introduction

20. My Other Job System for detecting positions of surgical instruments relative to patients’ bodies Embedded, real-time system Detect phase angles from transmitted microwaves Convert into positions and orientations of objects Programmed in LabView A graphical, object-oriented, data-flow language Introduction

21. Questions? Introduction

22. The C Language First created to develop Unix – late 1960s Kernighan & Ritchie, 1stedition – 1978 ANSI C – 1988 Kernighan & Ritchie, 2nd edition, 1988 Implemented by nearly all C compilers C95, C99 Minor additions (to be noted as we get to them) Most major C compilers Introduction

23. Successors to C C++ Developed by Bjarne Stroustrup at Bell Labs Major extension of C to support object-oriented programming Attempted to preserve syntax and structure of C Java Rewrite of C++ at Sun Microsystems Machine independence, portability Ability to embed in web pages Huge libraries of packages for all kinds of stuff Introduction

24. Your First C Program #include <stdio.h> int main () { printf(″Hello, World!\n″); return 0; } Introduction

25. Fundamental Rule in C Introduction • Every identifier must be declared before it can be used in a program • Definition:– “identifier” • A sequence of letters, digits, and ‘_’ • Must begin with a letter or ‘_’ • Case is significant • Upper and lower case letters are different • Must not be a “reserved word” — see p. 192 • Definition:– “declare” • Introduce an identifier and the kind of entity it refers to • Optionally, define associated memory or program

26. So where is printf declared? #include <stdio.h> int main () { printf(″Hello, World!\n″); return 0; } Introduction

27. So where is printf declared? #include <stdio.h> int main () { printf(″Hello, World!\n″); return 0; } Answer: in this file! Introduction

28. Your First C Program #include <stdio.h> int main () { printf(″Hello, World!\n″); return 0; } • A header file • Contains declarations of names, functions, data, of things defined elsewhere • E.g., by the system • Text of the header file is inserted by compiler into your program • As if you wrote it yourself! Introduction

29. Your First C Program #include <stdio.h> int main () { printf(″Hello, World!\n″); return 0; } • A function declaration • Declares the name and defines the body of your function • May take arguments, returns an integer • main is a special name to the system • The place where a program “starts” Introduction

30. Your First C Program #include <stdio.h> int main () { printf(″Hello, World!\n″); return 0; } • Body of the function • Defines what the function “does” • Sequence of statements • Each does a step of the function • Enclosed in curly brackets • { } Introduction

31. Your First C Program #include <stdio.h> int main () { printf(″Hello, World!\n″); return 0; } • Call to another function • In this case, a function defined by the system • Prints some data on standard output Introduction

32. Your First C Program #include <stdio.h> int main () { printf(″Hello, World!\n″); return 0; } • Argument to printf – a constant string • Enclosed in straight double quotes • Note the new-line character ′\n′ at the end Introduction

33. Your First C Program #include <stdio.h> int main () { printf(″Hello, World!\n″); return 0; } • A return statement • return is a reserved word in C • main should return zero if no error; non-zero if error Introduction

34. Your First C Program #include <stdio.h> int main () { printf(″Hello, World!\n″); return 0; } • Note that statements typically end with semicolons • So compiler can tell where end of statement is Introduction

35. Questions? Write, compile, and execute this program in Lab session tomorrow Introduction

36. What happens to your program … …after it is compiled, but before it can be run? Introduction

37. Example #include <stdio.h> int main () { printf (″Hello, world\n″); } Symbol defined in your program and used elsewhere main Symbol defined elsewhere and used by your program printf Introduction

38. Static Linking and Loading Printf.c HelloWorld.c gcc Library gcc Printf.o ar HelloWorld.o Linker a.out(or name ofyour command) Loader Memory Introduction

39. Compiling Your Program gcc HelloWorld.c Compiles the program in HelloWorld.c, links with any standard libraries, puts executable in a.out You should find HelloWorld.o in your directory gcc –o hello_world HelloWorld.c Same as above, but names the executable file hello_world instead of a.out gcc –lrt HelloWorld.c Searches library named rt.a for functions to link(in addition to standard libraries) Introduction

40. Compiling Your Program (continued) gccfoo.cbar.chelp.c Compiles the programs foo.c, bar.c, and help.c, links with standard libraries, executable in a.out You should find foo.o, bar.o, and help.o in your directory gcc –o Lab2 foo.cbar.chelp.c Same as above, but names the executable file Lab2 gcc –c foo.cbar.chelp.c Compiles foo.c, bar.c, and help.c to foo.o, bar.o, and help.o but does not link together Introduction

41. Questions? Introduction

42. Short Break Please fill out survey questionnaire Introduction