1. Introduction to C Programming Introduction

2. Bookss The Waite Groups Turbo C Programming for PC, Robert Lafore, SAMSs C How to Program, H.M. Deitel, P.J. Deitel, Prentice Hall

3. What is C?s C s A language written by Brian Kernighan and Dennis Ritchie. This was to be the language that UNIX was written in to become the first "portable" languageIn recent years C has been used as a general-purpose language because of its popularity withprogrammers.

4. Why use C? s Mainly because it produces code that runs nearly as fast as code written in assembly language. Some examples of the use of C might be: Operating Systems Language Compilers Assemblers Text Editors Print Spoolers Network Drivers Modern Programs Data Bases Language Interpreters UtilitiesMainly because of the portability that writing standard C programs canoffer

5. Historys In 1972 Dennis Ritchie at Bell Labs writes C and in 1978 the publication of The C Programming Language by Kernighan & Ritchie caused a revolution in the computing worlds In 1983, the American National Standards Institute (ANSI) established a committee to provide a modern, comprehensive definition of C. The resulting definition, the ANSI standard, or "ANSI C", was completed late 1988.

6. Why C Still Useful?s C provides: x Efficiency, high performance and high quality s/ws x flexibility and power x many high-level and low-level operations middle level x Stability and small size code x Provide functionality through rich set of function libraries x Gateway for other professional languages like C C++ Javas C is used: x System software Compilers, Editors, embedded systems x data compression, graphics and computational geometry, utility programs x databases, operating systems, device drivers, system level routines x there are zillions of lines of C legacy code x Also used in application programs

7. Software Development Methods Requirement Specification Problem Definitions Analysis Refine, Generalize, Decompose the problem definitions Design Develop Algorithms Implementation Write Codes Verification and Testing Test and Debug the code

8. Development with Cs Four stages Editing: Writing the source code by using some IDE or editor Preprocessing or libraries: Already available routines compiling: translates or converts source to object code for a specific platform source code -> object code linking: resolves external references and produces the executable module Portable programs will run on any machine but.. Note! Program correctness and robustness are most important than program efficiency

9. Programming languagess Various programming languagess Some understandable directly by computerss Others require translation steps Machine language Natural language of a particular computer Consists of strings of numbers(1s, 0s) Instruct computer to perform elementary operations one at a time Machine dependant

10. Programming languagess Assembly Language English like abbreviations Translators programs called Assemblers to convert assembly language programs to machine language. E.g. add overtime to base pay and store result in gross pay LOAD BASEPAY ADD OVERPAY STORE GROSSPAY

11. Programming languagess High-level languages To speed up programming even further Single statements for accomplishing substantial tasks Translator programs called Compilers to convert high-level programs into machine language E.g. add overtime to base pay and store result in gross pay grossPay = basePay + overtimePay

12. History of Cs Evolved from two previous languages BCPL , Bs BCPL (Basic Combined Programming Language) used for writing OS & compilerss B used for creating early versions of UNIX OSs Both were typeless languagess C language evolved from B (Dennis Ritchie Bell labs) ** Typeless no datatypes. Every data item occupied 1 word in memory.

13. History of Cs Hardware independents Programs portable to most computerss Dialects of C Common C ANSI C ANSI/ ISO 9899: 1990 Called American National Standards Institute ANSI Cs Case-sensitive

14. C Standard Librarys Two parts to learning the C world Learn C itself Take advantage of rich collection of existing functions called C Standard Librarys Avoid reinventing the wheels SW reusability

15. Basics of C Environments C systems consist of 3 parts Environment Language C Standard Librarys Development environment has 6 phases Edit Pre-processor Compile Link Load Execute

16. Basics of C Environment Program edited inPhase 1 Editor Disk Editor and stored on disk PreprocessorPhase 2 Preprocessor Disk program processes the code Creates object codePhase 3 Compiler Disk and stores on disk Links object codePhase 4 Linker Disk with libraries and stores on disk

17. Basics of C Environment Primary memory Puts program inPhase 5 Loader memory Primary memory Takes each instructionPhase 6 CPU and executes it storing new data values

18. Simple C Program/* A first C Program*/#include void main(){ printf("Hello World n");}

19. Simple C Programs Line 1: #include s As part of compilation, the C compiler runs a program called the C preprocessor. The preprocessor is able to add and remove code from your source file.s In this case, the directive #include tells the preprocessor to include code from the file stdio.h.s This file contains declarations for functions that the program needs to use. A declaration for the printf function is in this file.

20. Simple C Programs Line 2: void main()s This statement declares the main function.s A C program can contain many functions but must always have one main function.s A function is a self-contained module of code that can accomplish some task.s Functions are examined later.s The "void" specifies the return type of main. In this case, nothing is returned to the operating system.

21. Simple C Programs Line 3: {s This opening bracket denotes the start of the program.

22. Simple C Programs Line 4: printf("Hello World From Aboutn");s Printf is a function from a standard C library that is used to print strings to the standard output, normally your screen.s The compiler links code from these standard libraries to the code you have written to produce the final executable.s The "n" is a special format modifier that tells the printf to put a line feed at the end of the line.s If there were another printf in this program, its string would print on the next line.

23. Simple C Programs Line 5: }s This closing bracket denotes the end of the program.

24. Escape Sequences n new lines t tabs r carriage returns a alerts backslashs double quote

25. Memory conceptss Every variable has a name, type and values Variable names correspond to locations in computer memorys New value over-writes the previous value Destructive read-ins Value reading called Non-destructive read-out

26. Arithmetic in CC operation Algebraic CAddition(+) f+7 f+7Subtraction (-) p-c p-cMultiplication(*) bm b*mDivision(/) x/y, x , x y x/yModulus(%) r mod s r%s

27. Precedence orders Highest to lowest () *, /, % +, -

28. ExampleAlgebra: z = pr%q+w/x-yC: z = p * r % q + w / x y ;Precedence: 1 2 4 3 5

29. ExampleAlgebra: a(b+c)+ c(d+e)C: a * ( b + c ) + c * ( d + e ) ;Precedence: 3 1 5 4 2

30. Decision Makings Checking falsity or truth of a statements Equality operators have lower precedence than relational operatorss Relational operators have same precedences Both associate from left to right

31. Decision Makings Equality operators == !=s Relational operators < > =

32. Summary of precedence orderOperator Associativity () left to right* / % left to right + - left to right< >= left to right== != left to right = left to right

33. Assignment operatorss =s +=s -=s *=s /=s %=

34. Increment/ decrement operatorss ++ ++as ++ a++s -- --as -- a--

35. Increment/ decrement operatorsmain(){ int c; c = 5; 5 printf(%dn, c); 5 printf(%dn, c++); 6 printf(%dnn, c); c = 5; printf(%dn, c); 5 6 printf(%dn, ++c); 6 printf(%dn, c); return 0;}

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