Introduction to Programming ( 計算機程式設計 ) Chapter 1 Getting Ready

Transcription

1 Introduction to Programming ( 計算機程式設計 ) Chapter 1 Getting Ready Meng-Lin Li ( 李夢麟 ) mlli@ee.nthu.edu.tw Department of Electrical Engineering National Tsing Hua University 1

2 Why C, C, Why not C++? Spirit of ofc++ --Object-Oriented Programming (OOP) 2

3 What computers do C s features What Will You Learn? Steps needed to write programs Compilers and linkers C Standards 3

4 What computers do C s features What Will You Learn? Steps needed to write programs Compilers and linkers C Standards 4

5 A computer Programming Environment A workstation ( 工作站 ) : Sun ( 昇陽 ) SPARCstation-10 A personal computer (PC) : Acer ( 宏碁 ) FT100 Computer hardware ( 計算機硬體 ) Hardware environment Computer software ( 計算機軟體 ) Software environment 5

6 Pictures of of4th Generation Computer 6

7 Computer Hardware von Neumann architecture CPU System bus I/O bus Secondary storage memory I/O devices 7

8 Computer Hardware Bus A high-speed communication channel between hardware components of a computer Central processing unit (CPU, 中央處理單元 ) Brain of the computer, performing computation and controlling the computer Main memory ( 主記憶體 ) Hardware that is capable of quickly storing and retrieving information RAM (random access memory) in a workstation Secondary memory ( 次記憶體 ) Large-volume storage device that dose not require electrical power to store permanent data. hard disk 8

9 Peripherals ( 週邊設備 ) Computer Hardware Hardware devices that perform input and output functions Interactive ( 互動式 ) communication between users and machines Keyboard ( 鍵盤 ) : standard input ( stdin, in C) device Monitor ( 監視器 ) : standard output ( stdout, in C) device Printer ( 印表機 ) : output device 9

10 Computer Software Operating system ( 作業系統 ) A software system to coordinate all the resources in a computer UNIX (based), Windows 10

11 CPU and Memory (Fetch and Execute) reg 0 Register 0 Program counter 0x x00 Memory add R4, R1, R2 reg Instruction register 0x04 reg add R4, R1, R2 0x08 reg 3 0x0c reg x10 reg 5 Control logic 0x ALU Memory Address Register to/from memory 11

12 Data Path for Register File Program Execution reg 0 Register 0 Program counter 0x x00 Memory add R4, R1, R2 reg Instruction register 0x04 reg add R4, R1, R2 0x08 reg 3 0x0c reg x10 reg 5 Control logic 0x ALU Memory Address Register to/from memory 12

13 Program Execution of of Addition (Simplified Version) Fetch Copy the instruction in memory Copy the number in memory location 2000 to register 1 Copy the number in memory location 2004 to register 2 Add the contents of register 2 to the contents of register 1, leaving the answer in register 1 Copy the contents of register 1 to memory location 2008 Execute 13

14 Program Execution Follows Machine Language (Binary, the world of 0 and 1) 14

15 An Example MIPS code (Binary representation) Guess what the MIPS code does? The c code a = b + c (High level language understandable to us) is transformed into the machine code By what? 15

16 What computers do C s features What Will You Learn? Steps needed to write programs Compilers and linkers C Standards 16

17 Why C instead of ofother fancy languages, like Basic, Fortran, Pascal, Delphi, C++, C#, JAVA, Matlab, Labview and so soon? (What? $%^& Google it!) 17

18 High level language Understandable to us Why C? Design features Top-down planning, structured programming, and modular design Efficiency Portability C programs written on one system can be run on other systems with little or no modification (C compilers are available for about 40 systems) Power and flexibility Programmer Oriented Access to hardware, manipulate individual bits in memory Shortcomings The danger comes with the flexibility C s freedom requires added responsibility to the programmers 18

19 What computers do C s features What Will You Learn? Steps needed to write programs Compilers and linkers C Standards 19

20 Seven Steps of ofprogramming 7. Maintain and modify the program 6. Test and debug ( 除錯 ) the program (Bugs, Mistakes) 5. Run the program (Executable file) 4. Compile 3. Write the code (Source code) 2. Design the program with a flow chart ( 流程圖 ) 1. Define the program objects 20

21 Write the Codes by by Text Editor Text editor ( 編輯器 ) An interface software for a user to write a C program The program will be stored in the file system as a file with a name ended in.c, called a source code file hello.c wordcount.c power.c basename extension Filename ( 副檔名 ) 工具 -> 資料夾選項 -> 檢視 ->Disable 隱藏副檔名 <HINT> I prefer *.cpp as the extension. Why? 21

22 22

23 Text Editors in inunix System vi A standard text editor in UNIX with high efficiency vim An improved version of vi in UNIX Official website Good tutorial website: GNU emacs 23

24 Text Editors in inwindows NotePad ( 附屬應用程式 -> 記事本 ), not WordPad) UltraEdit-32 24

25 A C Program hello.c ( Text file) /* The famous C program in K&R which prints the words hello, world. */ #include <stdio.h> int main(void) { printf( hello, world\n ); return 0; } How and where to write it? Demo in Windows 1. Pure text editor 2. IDE (Integrated development environment, e.g., Dev-C++) 25

26 Notepad->Create *.txt->rename it to *.cpp->double click to edit 26

27 What computers do C s features What Will You Learn? Steps needed to write programs Compilers and linkers C Standards 27

28 Compiler And Linker Compiler ( 編譯器 ) To translate a C program s source code file to an object code file (a machine language code) Linker ( 連結器 ) To link the user object code with two other system object codes into an executable file (a complete machine language code) The standard start-up code an interface between your program and the operating system The standard C library code routines called by the user object code 28

29 A Translation Hierarchy (( 階級制 )) C program source code Complier Assembly language program Assembler Object code:machine language module Object:Start-up code (machine language) Object : Library routines (machine language) Linker Executable code:machine language program Loader Memory 29

30 C Compilers in inunix System cc The standard compiler in Unix system The compiler command is cc inputfilename gcc Created as a part of the GNU operating system The compile command is gcc o outputfilename inputfilename 30

31 C Compilers in inwindows Free Dev-C++ (Demo compiling and running the program) Visual C++ Borland C++ (Builder) 31

32 32

33 What computer do C s features What Will You Learn? Steps needed to write programs Compilers and linkers C Standards 33

34 Whence C? Dennis Ritchie of Bell Labs created C in 1972 as he and Ken Thompson worked on designing the Unix operating system. It was named "C" because many of its features were derived from an earlier language Thompson s B language 34

35 K&R C or classic ( 古典 ) C Evolution (( 演化 )) of ofc K&R means Brian Kernighan and Dennis Ritchie Based on the 1st edition ( 第一版 ) of their book The C Programming Language in 1978 The C language is defined but not the C library ( 函式庫 ) The C library in the UNIX implementation became a de facto ( 實質上的 ) standard ( 標準 ) 35

36 ANSI/ISO C Evolution (( 演化 )) of ofc Both the C language and a standard C library are defined ANSI = American National Standards Institute ANSI C at 1989 ISO = International Organization of Standardization ISO C at 1990 ANSI C and ISO C are essentially the same and referred to as C90 36

37 Evolution (( 演化 )) of ofc C99 Standard The newest standard established by a joint ANSI/ISO committee Keeping the spirit of C small, simple and efficient Internationalization ( 國際化 ) Dealing with international character sets Correction of deficiency ( 缺點 ) Codify ( 編纂 ) existing practice to address evident deficiencies Meeting the needs of moving C to 64-bit processors Improvement of computational usefulness 37

38 Last Thing You Have to toknow in inadvance 38

39 Number Systems Decimal (base 10) number system ( 十進位 ) 109 = 1 x 10^2 + 0 x 10^1 + 9 x 10^0 Binary (base 2) number system ( 二進位 ) = 1 x 2^6 + 1 x 2^5 + 0 x 2^4 + 1 x 2^3 + 1 x 2^2 + 0 x 2^1 + 1 x 2^0 = 109 (base 10) Octal (base 8) number system ( 八進位 ) 0155 = 1 x 8^2 + 5 x 8^1 + 5 x 8^0 = 109 (base 10) = Hexadecimal (base 16) number system ( 十六進位 ) 0x6d = 6 x 16^ x 16^0 = 109 (base 10) = a = 10, b = 11, c = 12, d = 13, e = 14, f = 15 39

40 Data type Main Chapter Organization Strings, and formatted input and output Operators, expressions, and statements Looping Condition control: branching and jumps Functions Array and pointers File input/output 40

41 What computers do C s features Have You Learned? Steps needed to write programs Compilers and linkers C Standards (Number Systems) 41

42 Take Home Practices Create the text file hello.cpp and write the most famous C program Hello, the world! by the introduced text editors If you like to, try to compile and run the program by the ways introduced in in-class demos. 42

43 Welcome to tothe World of ofc ^_^ 43