C_Programming_Language_-Introduction_of_C_.ppt

1、C Programming Language,Hong Song The School of Computer Science and Technology,Fall 2011,Introduction,Lecture One,Outline,Overview of Programs and Algorithms Overview of C Language Programming language Characteristics of C Essential Elements Simple Programming Examples How to do programming? Program

2、ming Process Programming Environment Programming style,Computer system,Hardware Software,Whats Computer System?,Overview of Programs and Algorithms,Software,program data document,What is Program?,programming language,A set of Characters and rules Can be interpreted by Computer,A set of programs,Prog

3、ram Design,Overview of Programs and Algorithms,Program -A list of computer instructions Program = Data Structure + Algorithm + Language,statements,Data, structure, algorithm,Program design- How to solve the problem algorithmic design + coding,Overview of Programs and Algorithms,e.g,How to calculate

4、the area of a swimming pool?,four steps Program design,Overview of Programs and Algorithms,Analyze,Confirm,Coding,Data structure and Algorithm,Problem Model,Debug,Programming language,Result,Steps,Keywords,- A strategy for solving a problem (a list of steps),What is Algorithm (算法),Overview of Progra

5、ms and Algorithms,Algorithm must be: Clearly and unambiguously defined. Effective, in the sense that its steps are executable. Finite, in the sense that it terminates after a bounded number of steps,Essential factors: Operator + Control,Arithmetic Operator: ,Logical Operator: and, or, not,Relational

6、 Operator: ,Transmit Operator: input, output, assign,sequence （順序）,Operator,Control,decision (branch)（分支/選擇）,repetition (loop)（循環(huán)）,Overview of Programs and Algorithms,Overview of Programs and Algorithms,Practical Problems: There is a black ink bottle and a blue one, But Lily filled black ink into th

7、e blue bottle and blue ink into the black one by mistake. How to exchange them to the write bottle?,Step1: Get a blank red bottle. Step2: Pouring blue ink from black bottle into the red one. Step3: Pouring black ink from blue bottle into the black one. Step4: Pouring blue ink from red bottle into th

8、e blue one. Step5: End.,Analysis,A blank bottle needed,Some Presenting Forms: Human Language Flowchart Pseudo-code,Overview of Programs and Algorithms,Presenting Algorithm,Symbols in Flowchart Provided by ANSI (American National Standard Institute),Overview of Programs and Algorithms,Overview of Pro

9、grams and Algorithms,e.g Swapping two variables,Outline,Overview of Programs and Algorithms Overview of C Language Programming Language Characteristics of C Essential Elements Simple Programming Examples How to do programming? Programming Process Programming Environment Programming style,Programming

10、 Language,Natural Language Human C+ language #include main() std:cout 1 + 1; ,The development of Programming language,1960 Algol-60,1950,1960,1970,1980,1990,Fortran,Algol-60,Cobol,Simula,Pascal,Smalltalk,Ada,C,C+,Java,1963 CPL,CPL,BCPL,B,1967 BCPL,1970 B,1972 C,1985 C+,ANSI C,Overview of C Language,

11、What is C?,a general-purpose computer programming language,characters, syntax, structure, control statement, data type, operators,Operating systems, Compiler, Drivers,Characteristics of C,Overview of C Language,Small size C is modular Loose typing Structured language Low level programming readily av

12、ailable C has a very powerful set of operators C is the basis for C+ and Java C efficient on most machines,C Program Structure,Overview of C Language,program,functions,statements,expressions,Operands + operators,Characters,Character,Numeral: 0 1 2 9,Letter: ABCZ a b cz,Operator: + - = ,Others: r n t

13、 ,Statement,Expression,Control,branch: if-else; switch loop: for; while Jump: break; goto,Compound,Essential Elements,Function:,main( ), print(),Print the words: Hello, world you have to: Create the program text Compile it successfully Run it Get the output,The First Program Is Always The Same,“Hell

14、o, world.” Program,The program is stored as a text file named hello.c .c identifies the file as a C program.,program comment,library inclusions,main function,/* File: hello.c This program prints the message “Hello, world.” on the screen. */ #include void main () printf (“Hello, world.n”); ,Compile i

15、t,Run it,e.g sum = n1 + n2, How to get sum?,void main () int n1, n2, sum ; n1 = 23 ; n2 = 89 ; sum = n1 + n2 ; printf(“sum is %d n”, sum) ; ,A program to add two numbers,/*main function*/ /*variables declaration */ /* assignment */ /*assignment expression */ /*output*/,void main( ) int n1, n2, sum;

16、scanf ( “%d, %d”, ,void main () int n1, n2, sum ; n1 = 23 ; n2 = 89 ; sum = n1 + n2 ; printf(“sum is %d n”, sum) ; ,How to add any two numbers?,Identifiers,the names for variables,data types, functions, file, arrays,pointers in program. Must be different from keywords. Create an identifier by specif

17、ying it in the declaration of a variable, type, or function. Once declared, the identifier can be used in later program statements to refer to the associated value.,How to define Identifier Letters sum=0; for(i=1; i10;i+) for(j=1;j10;j+) sum+=i*j ; printf(“%dn”,sum); ,Programming style,TERMS,Compiler 編譯系統(tǒng)Instruction