C語言英文課件Chapter 10

1、chapter 10 STRUCTURES AND UNIONS,A structure is a collection of one or more variables,possibly of different types,which are treated as a unit instead of as separate entities. 10.1 structure definition 10.2 structure variables citing and initialization 10.3 structure array 10.4 structure pointer 10.5

2、 link dispoing- application of structure pointer 10.6 union and enumeration 10.7 typedef,10.1 STRUCTURE TYPE AND DECLARATION OF STRUCTURE VARIABLES,THE STRUCTURE TYPE ,IN C LANGUAGE ，is the counterpart as “record” in other advanced language. 一、question emerging STUDENT SCORES MANAGE TABLE CANOT DEAL

3、 WITH 2D ARRAYS,DIFFERENT TYEPES！,二、 structure type declaration Common usage： struct structure typename datatype member1; datatype member2; datatype membern; ;,struct student int num; char name20; char sex; int age; float score1; float score2; ;,Type name,struct student,demonstration： 1、the rules to

4、 name“structure type name”and “member name” ,are same with the variables. 2、the definitions of variables can be seperated or in a same line like the instance below eg. struct date int year, month, day; ; 3、 the definitions of variables could be basic types or another structure type which has been de

5、clarated. eg.the type”birthday” in the eg. Of structure type std_info is a definited structure type -date,三、 STRUCTURE VARIABLES DECLARATION Structure type（user definition） Standart type（system definition） 1、indirect declaration first declare the structure type,then the structure variables,The same

6、usage,struct student int num; char name20; char sex; int age; float score1; float score2; ;,struct student stu1, stu2;,num name sex age score1 score2,stu1,2、 direct declaration (1)definite the structure variable,when definiting the structure type； (2)definite the structure variable directly；,(1) str

7、uct student int num; char name20; float score2; stu1, stu2;,(2) struct int num; char name20; float score2; stu1, stu2;,3、demonstration (1)differ structure type and variable,which are completely different conception ,just as type int and variable of int (2)member names in structure ,may be same as ot

8、her variables in program, stand for different objects,eg10.1 creat a structure reffering to basic information of a student to store the details of a student struct date /*data structure type made of year,month and day*/ int year; int month; int day; ; struct std_info/*student information structure t

9、ype*/ int num; /*made of name,sex,birthday,etc*/ char name12; char sex; struct date birthday; float score1,score2; ;,10.2 CITING AND INITIALIZATIONS OF STUCTURE VARIABLES,例10.2 make use of the former stucture type struct std_info，to definite a structure type stu to store and print the student detail

10、s #include“struct.h”struct std_info stu = 1002,”Zhang San”,M, 1980,9,20,98.2,86.5;main() printf(No: %dn,stu.num); printf(Name: %sn,); printf(Sex: %cn,stu.sex); printf(Birthday: %d-%d-%dn,stu.birthday.year, stu.birthday.month, stu.birthday.day); ,result： No: 1002 Name: Zhang San Sex: M Birthd

11、ay:1980-9-20,1、 INITIALIZATIONS OF STUCTURE variable structtype struct_variable=initial value list eg，struct std_info stu = “000102”,”Zhang San”,M, 1980,9,20; note：data type of initial value should be consistent with the members in structure variable,or there will be error. 2、citing rules of structu

12、re variable member operator“.” while citing the member in structure ,use operator”.” ; citing format:structure variable.member eg,stu.num； ,etc。,NOTE：if a member itself is a structure type,a multilevel member operation is needed to cite the lowest member. Expanding format： structure variable

13、. member.child-member. Lowest member Eg.： stu.birthday.year stu.birthday.month stu.birthday.day betaking the lowest member is equal to common variable of the same type.,10.3 STRUCTURE ARRAYS,Structure arrays：an array made by structure type data which is as element in structure. Every array element:i

14、nclude all members of structure 例10.3 use structure array to store and print the student scores manage table below.,stu0 stu1 stu2 stu3,struct student /*lay the definition of structure type outside function*/ int num; char name12; char sex; int age; float score1; float score2; ; struct stdent stu4=1

15、001,”Zhang Xin”,M,20, 87, 91, 1002,”Wang Li”, F,20, 98, 96, 1003,”Chen Fong”,M,21,86, 90, 1004,”Li Xiaopen”, M,20,77, 86;,Store in file“struct.h”,#includestruct.h” main() int i; /*print list head, “stands for one backspace*/ printf(No.NameSexAgesoc1 sco2n); /*output basic details of 4 students*/ for

16、(i=0; i4; i+) printf(%-5d,stui.num); printf(%-12s,); printf(%-4c,stui.sex); printf(%-4d,stui.age); printf(%-5.1f,stui.score1); printf(%-5.1fn,stui.score2); ,Running result： No. Name Sex Age soc1 sco2 1001 Zhang Xin M 20 87 91 1002 Wang Li F 20 98 96 1003 Chen Fong M 21 86 90 1004 Li Xiaopen

17、 M 20 77 86,eg10.4use arrays of structure as funtion parameters #includestruct.h void print_stulist(struct student stu) int i; printf(No. Name Sex Age soc1 sco2n); for(i=0; i4; i+) printf(%-5d,stui.num); printf(%-12s,); printf(%-4c,stui.sex); printf(%-4d,stui.age); printf(%-5.1f,stui.score1

18、); printf(%-5.1fn,stui.score2); ,Use Array of structure as formal parameter,void sort(struct student st) int i,j; struct student temp; for(i=0;i4-1;i+) for(j=i+1;j4;j+) if(sti.score1stj.score1) temp=sti; sti=stj; stj=temp; ,main() clrscr(); print_stulist(stu); sort(stu); printf(list after sorted:n);

19、 print_stulist1(stu); getch(); ,Structure array as formal parameter,Running result： No. Name Sex Age soc1 sco2 1001 Zhang Xin M 20 87 91 1002 Wang Li F 20 98 96 1003 Chen Fong M 21 86 90 1004 Li Xiaopen M 20 77 86 list after sorted: No. Name Sex Age soc1 sco2 1002 Wang Li F 20 98 96 1001 Zhang Xin M

20、 20 87 91 1003 Chen Fong M 21 86 90 1004 Li Xiaopen M 20 77 86,10.4 pointer pointed to data type of structure,Pointer of structure variable：structure variable exists in the starting position of the storage. void print_stulist(struct student stu) int i; printf(No. Name Sex Age soc1 sco2n); for(i=0; i

21、4; i+) printf(%-5d,stui.num); printf(%-12s,); printf(%-4c,stui.sex); printf(%-4d,stui.age); printf(%-5.1f,stui.score1); printf(%-5.1fn,stui.score2); ,modify！ Use pointer which point to structure as formal parameter,eg10.5 use pointer to call member of the structure variable void print_stuli

22、st1(struct student *p) int i; printf(No. Name Sex Age soc1 sco2n); for(i=0; i4; i+) printf(%-5d,(*(p+i).num); printf(%-12s,(*(p+i).name); printf(%-4c,(*(p+i).sex); printf(%-4d,(*(p+i).age); printf(%-5.1f,(*(p+i).score1); printf(%-5.1fn,(*(p+i).score2); ,If use for(i=0;i4;i+,p+), then how to modify？,

23、eg10.5 use pointer to call every member of the structure variable void print_stulist1(struct student *p) int i; printf(No. Name Sex Age soc1 sco2n); for(i=0; i4; i+，p+) printf(%-5d,(*p).num); printf(%-12s,(*p).name); printf(%-4c,(*p).sex); printf(%-4d,(*p).age); printf(%-5.1f,(*p).score1); printf(%-

24、5.1fn,(*p).score2); ,If the pointer has been pointing to structure variable v，then when： struct student var, *p= The 3 forms below are equal： (1) var.member name (2) (*p).member name (3) p-member name thoughts：how to input every member of stui by keyboard?,10.5 linklist disposingapplication of struc

25、ture pointer,10.5.1 linklist overview 一Dynamic data structure element number fluctuates by program running. cf. data structure of static state（eg.array）,confirm ing its size when definiting. 二 Dynamic data structure implement in virtue of ： 1、pointer points to structure type 2、structure type includi

26、ng pointer data linklist：a simple dynamic data structure. head,10.5.2 creating linklist 一、description of linklist node structureeg. struct node int num; /*data area*/ struct node *next; /*pointer area*/ ; 二、 function of disposing linklist 1、 mallocapply memory storage void *malloc(unsigned int size)

27、 eg. struct node *p; p=(struct node*)malloc(sizeof(struct node);,p,2、 freeset storage area free void free(void *p) 三、create linklist 例10.6according to a series of nonnegative integers, input by keyboard ,to create a linklist,and output the value of every data area by order eg：input 1 3 2 5 0，create

28、linklist such as：,/*1.creat new node，pointed by head pointer*/ head=(struct node*)malloc(LEN); last=head; /*tail pointer points to node of tail*/,/*2.input x;create new node p;store x to num area of node p*/ scanf(%d,/*3.add p to the linklist tail*/ last-next=p;,/*4.last move backwards*/ last=p;,Rep

29、eat 24，when x0,/*set pointer area NULL which was pointed by tail node pointer，head pointer move backwards (deleting head node)*/ last-next=NULL; head=head-next;,main() struct node *head,*p,*last; int x; head=(struct node*)malloc(LEN); last=head; while(1) scanf(%d,#define NULL 0 #define LEN sizeof(st

30、ruct node) struct node int num; struct node *next; ;,p=head; head=head-next; free(p);,/*output linklist*/ printf(“data of the linklist are:”) p=head; while(p!=NULL) printf(%5d,p-num); p=p-next; printf(n); getch(); Running result： 1 3 2 5 0 data of the linklist are:1 3 2 5,Q：make 2 functions for crea

31、ting linklist and output linklist：,1.struct node *creat(void) 2.void print(struct node *head),struct node *creat(void)/*create linklist function*/ struct node *head,*p,*last; int x; head=(struct node*)malloc(LEN); last=head; while(1) scanf(%d, ,2、output linklist 1、install linklist 四、realizing by fun

32、ction：,void print(struct node *head)/*output linklist function*/ struct node *p; p=head; while(p!=NULL) /*traversing the linklist*/ printf(%5d,p-num); p=p-next; printf(n); getch(); main() struct node *head; printf(input data to creat linklist(end by =0):n); head=creat(); printf(the data of linklist:

33、n); print(head); ,Q：computing the maxinum and mininum of the data node,10.5.3 insert operation to linklist eg10.8 create a function insert() to realize inserting a new node which data is x after to the Ist node which is pointed by head. analysis ： comon situation pre-inserted： after-inserted： standa

34、rt consideration： along the pointer area of the node to find the ist node,finally insert new node after the ist node by linklist head pointer,Special situation： 1、null list pre=inserted：head=NULL after-inserted： 2、i=0 pre-inserted： after-inserted ： 3、i out-of -range（ithe number of node） disposing ma

35、nner：(1)error (2)insert to the tail,struct node *insert(struct node *head, int i,int x) struct node *s,*p; s=(struct node*)malloc(LEN); s-num=x; if(head=NULL) head=s; s-next=NULL; /*1、insert to the null linklist*/ else if(i=0) /*non-null linklist*/ s-next=head; head=s; /*2、new node as new head node

36、of linklist*/ else p=head; /*lookup the ist node(pointed by p)*/ for(; p!=NULL ,main() struct node *head; int i,x; printf(input data to creat linklist(end by =0):n); head=creat(); printf(the data of linklist:n); print(head); printf(insert: i,x=); scanf(%d%d, ,10.5.4 the delete operation to link list

37、 eg10.8 design a function delete() ，to delete the node whose data is x in the link list。 Common situation： Pre-deleted： After-deleted： q=head; p=q-next;/*lookup the node whose value is x*/ for(; p-num!=x ,espescial： 1、NULL list head=NULL error information 2、delete the head node pre-deleted： after-de

38、leted： 3、no such node error information,struct node *delete_list(struct node *head,int x) struct node *p,*q; if(head=NULL) /*1、blank list*/ printf(Error! The list is empty.n); else if(head-num=x) /*2、delete the first node*/ head=head-next; else q=head;p=q-next; for(; p-num!=x ,10.5.5 colligated exam

39、ple：menu program designing,/* = sorted link_list operater = */ /* Designed by Sun Qiaoping */ #include stdio.h; #define NULL 0 #define LEN sizeof(struct node) struct node int num; struct node *next; ; char menu(void); void print(struct node *head); struct node *insert_sortedlist(struct node *head, i

40、nt x); struct node *creat_sortedlist(void); struct node *delete_list(struct node *head,int x);,main() struct node *head=NULL; int i,x,flag=1; char ch; do ch=menu(); clrscr(); switch (ch) case 1: head=creat_sortedlist(); break; case 2: printf(input a number to insert. x=); scanf(%d, ,/* =menu = */ ch

41、ar menu(void) char ch; clrscr(); printf( MENU n); /*puts()*/ printf( =n); printf( 1. creat n); printf( 2. insert n); printf( 3. delete n); printf( 4. print n); printf( 0. exit n); printf( =n); printf(Input your choice(0,1,2,3,4):); ch=getchar(); return(ch); ,/* = insert = */ struct node *insert_sort

42、edlist(struct node *head, int x) struct node *s,*p,*q; s=(struct node*)malloc(LEN); s-num=x; if(head=NULL) /*insert to a blank list*/ head=s; s-next=NULL; else if(xnum) /*insert to head of list*/ s-next=head; head=s; else q=head;p=q-next; /*lookup the place to insert*/ for(; p!=NULL ,Pre-inserted： A

43、fter-inserted：,/* = creat = */ struct node *creat_sortedlist(void) struct node *head; int x; printf(input data to creat linklist(end by =0):n); head=NULL; while(1) scanf(%d, ,10.6 introduction to union and enum,10.6.1 union 1conception several variables of different type occupy the same segment of s

44、torage. 2Definition of union common situation：union u_name member list ； eg. union data int i; char ch; float f; ;,Same as definition of structure type,3Definition of Sharing variables (1)indirect definition eg： union data un1,un2,un3； (2)direct definitondefinite variables when definiting type eg. u

45、nion data int i; char ch; float f; un1, un2, un3; 4The storage length occupied by sharing variables：the length of longest member 5Citing to sharing variablesciting one by one 例如：un1.i、un1.ch、un1.f,5characteristic (1)System uses the overlaying techonology to realize memory sharing of the sharing vari

46、ablesmembers,so anytime there is only one member value to store and betake. eg，if un1.i=1, un1.ch=c, un1.f=3.14， un1.f is the valid member. (2)The address of Sharing variable is the same as that of every member. eg，un1un1.iun1.chun1.f (3)Cannot initialize sharing variable(note:structure variable is

47、permitted)； nor using sharing variable as function parameter，neither nor returning a sharing data by function,but its permitted to use a pointer pointed to sharing variable. (4)Sahring type can be used in structure definition,the reverse is ok!,10.6.2 enumeration 1Enumeration definition enum weekdays S