C语言英文课件10结构体和共用体

chapter10STRUCTURESANDUNIONSAstructureisacollectionofoneormorevariables,possiblyofdifferenttypes,whicharetreatedasaunitinsteadofasseparateentities.10.1structuredefinition

10.2

structurevariablescitingandinitialization10.3structurearray10.4structurepointer10.5

linkdispoing---applicationofstructurepointer10.6unionandenumeration10.7typedef10.1STRUCTURETYPEANDDECLARATIONOFSTRUCTUREVARIABLESTHESTRUCTURETYPE,INCLANGUAGE

，isthecounterpartas“record”inotheradvancedlanguage.一、questionemergingSTUDENTSCORESMANAGETABLE

CANOTDEALWITH2DARRAYSDIFFERENTTYEPES！1001ZhangXinM2087911002WangLiF2098961003ChenFongM2186901004LiXiaopenM207786

numnamesexagescore1score2二、structuretypedeclarationCommonusage：structstructuretypename

{

datatypemember1;

datatypemember2;

…………

datatype

membern;

};

structstudent{intnum;charname[20];charsex;

intage;floatscore1;floatscore2;};Typename

numnamesexagescore1score2structstudentdemonstration：1、therulestoname“structuretypename”and“membername”,aresamewiththevariables’.2、thedefinitionsofvariablescanbeseperatedorinasamelineliketheinstancebelow

eg.

structdate{intyear,month,day;};3、thedefinitionsofvariablescouldbebasictypesoranotherstructuretypewhichhasbeendeclarated.

eg.the

type”birthday”intheeg.Ofstructuretypestd_infoisadefinitedstructuretype--date三、

STRUCTUREVARIABLESDECLARATIONStructuretype（userdefinition）Standarttype（systemdefinition）1、indirectdeclaration

──firstdeclarethestructuretype,thenthestructurevariablesThesameusagestruct

student{intnum;charname[20];charsex;

intage;floatscore1;floatscore2;};structstudentstu1,stu2;

numnamesexagescore1score2stu12、directdeclaration(1)definitethestructurevariable,when

definitingthestructuretype；

(2)definitethestructurevariabledirectly；(1)struct

student{intnum;charname[20];……floatscore2;}stu1,stu2;(2)struct{intnum;charname[20];……floatscore2;}stu1,stu2;3、demonstration(1)differstructuretypeandvariable,whicharecompletelydifferentconception,justastypeintandvariableofint(2)membernamesinstructure,maybesameasothervariablesinprogram,standfordifferentobjects

[eg10.1]creatastructurerefferingtobasicinformationofastudenttostorethedetailsofastudentstructdate /*datastructuretypemadeofyear,monthandday*/{intyear;

intmonth;

intday;};structstd_info /*studentinformationstructuretype*/{intnum;/*madeofname,sex,birthday,etc*/charname[12];charsex;

structdatebirthday;floatscore1,score2;};numnamesexscore1score2

birthdayyearmonthday10.2CITINGAND

INITIALIZATIONSOF

STUCTUREVARIABLES

[例10.2]makeuseoftheformerstucturetypestructstd_info，todefiniteastructuretypestutostoreandprintthestudentdetails#include“struct.h”

structstd_infostu

={1002,”ZhangSan”,‘M’,{1980,9,20},98.2,86.5};

main()

{printf("No:%d\n",stu.num);

printf("Name:%s\n",);

printf("Sex:%c\n",stu.sex);

printf("Birthday:%d-%d-%d\n",stu.birthday.year,

stu.birthday.month,stu.birthday.day);}

numnamesexscore1score2

birthdayyearmonthdayresult：No:1002Name:ZhangSanSex:MBirthday:1980-9-20

1、INITIALIZATIONSOF

STUCTUREvariable

structtype

struct_variable={initialvalue

list}eg，structstd_infostu

={“000102”,”ZhangSan”,‘M’,{1980,9,20}};

note：datatypeofinitialvalueshouldbeconsistentwiththemembersinstructurevariable,ortherewillbeerror.2、citingrulesofstructurevariablememberoperator“.”whilecitingthememberinstructure,useoperator”.”;citingformat:structure

variable.member

eg,stu.num；

,etc。NOTE：ifamemberitselfisastructuretype,amultilevelmemberoperationisneededtocitethelowestmember.Expandingformat：

structurevariable.member.child-member.….LowestmemberEg.：

stu.birthday.year

stu.birthday.month

stu.birthday.daybetakingthelowestmemberisequaltocommonvariableofthesametype.10.3STRUCTUREARRAYSStructurearrays：anarraymadebystructuretypedatawhichisaselementinstructure.Everyarrayelement:includeallmembersofstructure[例10.3]usestructurearraytostoreandprintthestudentscoresmanagetablebelow.stu[0]stu[1]stu[2]stu[3]1001ZhangXinM2087911002WangLiF2098961003ChenFongM2186901004LiXiaopenM207786

numnamesexagescore1score2struct

student/*laythedefinitionofstructuretypeoutsidefunction*/{intnum;charname[12];charsex;

intage;floatscore1;floatscore2;};struct

stdentstu[4]={{1001,”ZhangXin”,’M’,20,87,91},

{1002,”WangLi”,‘F’,20,98,96},{1003,”ChenFong”,’M’,21,86,90},{1004,”LiXiaopen”,‘M’,20,77,86}};Storeinfile“struct.h”#include"struct.h”main(){inti;/*printlisthead,"□“standsforonebackspace*/printf("No.□□Name□□□□□□□□Sex□Age□soc1□sco2\n");/*outputbasicdetailsof4students*/for(i=0;i<4;i++){printf("%-5d",stu[i].num);printf("%-12s",stu[i].name);printf("%-4c",stu[i].sex);printf("%-4d",stu[i].age);printf("%-5.1f",stu[i].score1);printf("%-5.1f\n",stu[i].score2);}}Runningresult：

No.NameSexAgesoc1sco21001ZhangXinM208791

1002WangLiF2098961003ChenFongM2186901004LiXiaopenM207786[eg10.4]usearraysofstructureasfuntionparameters#include"struct.h"voidprint_stulist(structstudentstu[]){inti;

printf("No.NameSexAgesoc1sco2\n");for(i=0;i<4;i++){printf("%-5d",stu[i].num);printf("%-12s",stu[i].name);printf("%-4c",stu[i].sex);printf("%-4d",stu[i].age);printf("%-5.1f",stu[i].score1);printf("%-5.1f\n",stu[i].score2);}}UseArrayofstructureasformalparametervoidsort(structstudentst[]){inti,j;

structstudenttemp;for(i=0;i<4-1;i++)for(j=i+1;j<4;j++) if(st[i].score1<st[j].score1) {temp=st[i];

st[i]=st[j];

st[j]=temp; }}

main(){clrscr();

print_stulist(stu);

sort(stu);

printf("listaftersorted:\n");print_stulist1(stu);

getch();}Structurearrayasformalparameter

Runningresult：

No.NameSexAgesoc1sco21001ZhangXinM2087911002WangLiF2098961003ChenFongM2186901004LiXiaopenM207786listaftersorted:No.NameSexAgesoc1sco21002WangLiF2098961001ZhangXinM208791

1003ChenFongM2186901004LiXiaopenM20778610.4pointerpointedtodatatypeofstructurePointerofstructurevariable：structurevariableexistsinthestartingpositionofthestorage.voidprint_stulist(structstudentstu[]){inti;

printf("No.NameSexAgesoc1sco2\n");for(i=0;i<4;i++){printf("%-5d",stu[i].num);printf("%-12s",stu[i].name);printf("%-4c",stu[i].sex);printf("%-4d",stu[i].age);printf("%-5.1f",stu[i].score1);printf("%-5.1f\n",stu[i].score2);}}modify！Usepointerwhichpointtostructureasformalparameter

[eg10.5]usepointertocallmemberofthestructurevariablevoidprint_stulist1(structstudent*p){inti;

printf("No.NameSexAgesoc1sco2\n");for(i=0;i<4;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("%-5.1f\n",(*(p+i)).score2);}Ifusefor(i=0;i<4;i++,p++),thenhowtomodify？

[eg10.5]usepointertocalleverymemberofthestructurevariable

voidprint_stulist1(structstudent*p){inti;

printf("No.NameSexAgesoc1sco2\n");for(i=0;i<4;i++，p++){printf("%-5d",(*p).num);printf("%-12s",(*p).name);printf("%-4c",(*p).sex);printf("%-4d",(*p).age);printf("%-5.1f",(*p).score1);printf("%-5.1f\n",(*p).score2);}Ifthepointerhasbeenpointingtostructurevariablev，thenwhen：

structstudentvar,*p=&v;The3formsbelowareequal：

(1)var.membername(2)(*p).membername(3)p->membernamethoughts：howtoinputeverymemberofstu[i]bykeyboard?10.5linklist

disposing──applicationofstructurepointer10.5.1linklistoverview

一．Dynamicdatastructure

elementnumberfluctuatesbyprogramrunning.cf.datastructureofstaticstate（eg.array）,confirmingitssizewhendefiniting.二．Dynamicdatastructureimplement

invirtueof

：

1、pointerpointstostructuretype2、structuretypeincludingpointerdata

linklist：asimpledynamicdatastructure.head

3125NULL10.5.2creatinglinklist

一、descriptionoflinklistnodestructureeg.

structnode{intnum; /*dataarea*/

structnode

*next; /*pointerarea*/};二、

functionofdisposinglinklist1、malloc——applymemorystoragevoid*malloc(unsigned

intsize)

eg.

structnode*p;p=(structnode*)malloc(sizeof(structnode));

numnextp2、free——setstorageareafreevoidfree(void*p)

三、createlinklist[例10.6]accordingtoaseriesofnonnegative

integers,inputbykeyboard,tocreatealinklist,andoutputthevalueofeverydataareabyordereg：input13250，createlinklistsuchas：3125NULLhead

1

325NULLhead/*1.creatnewnode，pointedbyheadpointer*/head=(structnode*)malloc(LEN);last=head;/*tailpointerpointstonodeoftail*/head

last/*2.inputx;createnewnodep;storextonumareaofnodep*/scanf("%d",&x);p=(structnode*)malloc(LEN);p->num=x;/*3.addptothelinklisttail*/last->next=p;

1headlastp

1headplast/*4.lastmovebackwards*/last=p;1headlastpRepeat2~4，whenx≤0

132head5NULLlast/*setpointerareaNULLwhichwaspointedbytailnodepointer，headpointermovebackwards(deletingheadnode)*/last->next=NULL;head=head->next;main(){structnode*head,*p,*last;

intx;head=(structnode*)malloc(LEN);last=head;

while(1){scanf("%d",&x);if(x<=0)break;p=(structnode*)malloc(LEN); p->num=x; last->next=p; last=p;}last->next=NULL;head=head->next;

#defineNULL0#defineLEN

sizeof(structnode)structnode{intnum;

structnode*next;};p=head;head=head->next;free(p);

132head5NULL/*outputlinklist*/printf(“dataofthelinklistare:”)p=head;while(p!=NULL){printf("%5d",p->num); p=p->next;}

printf("\n");

getch();}Runningresult：13250dataofthelinklistare:1325Q：make2functionsforcreatinglinklistandoutputlinklist：1.structnode*creat(void)2.voidprint(structnode*head)structnode*creat(void)/*createlinklistfunction*/{structnode*head,*p,*last;

intx;head=(structnode*)malloc(LEN);last=head;while(1){scanf("%d",&x);if(x<=0)break;p=(structnode*)malloc(LEN);p->num=x; last->next=p; last=p; }last->next=NULL;p=head;head=head->next;free(p);return(head);}

2、outputlinklist1、installlinklist四、realizingbyfunction：voidprint(structnode*head)/*outputlinklistfunction*/{structnode*p;

p=head;while(p!=NULL)/*traversingthelinklist*/{printf("%5d",p->num); p=p->next;}

printf("\n");getch();}main(){structnode*head;

printf("inputdatatocreat

linklist(endby<=0):\n");head=creat();

printf("thedataoflinklist:\n");print(head);}Q：computingthemaxinum

andmininumofthedatanode10.5.3insertoperationtolinklist[eg10.8]createafunctioninsert()torealizeinsertinganewnodewhichdataisxaftertotheIstnodewhichispointedbyhead.analysis

：

comonsituationpre-inserted：

after-inserted：

standartconsideration：

alongthepointerareaofthenodetofindtheist

node,finallyinsertnewnodeaftertheistnodebylinklistheadpointerhead

1325NULL44ps

132head5NULLSpecialsituation：1、nulllistpre=inserted：head=NULLafter-inserted：2、i=0pre-inserted：

after-inserted：3、iout-of-range（i>thenumberofnode）

disposingmanner：(1)error(2)inserttothetailhead4NULL4s

132head5NULLhead

4125NULL3structnode*insert(structnode*head,int

i,intx){structnode*s,*p;s=(structnode*)malloc(LEN);s->num=x;if(head==NULL){head=s;s->next=NULL;}/*1、inserttothenulllinklist*/elseif(i==0) /*non-nulllinklist*/ {s->next=head;head=s;}/*2、newnodeasnewheadnodeoflinklist*/else {p=head;/*lookuptheist

node(pointedbyp)*/for(;p!=NULL&&i>1;p=p->next,i--);if(p==NULL) /*3、errorout-of-range*/

printf("Outoftherange,can'tinsert!\n");else /*4、commonsituation：ppointtotheistnode*/ {s->next=p->next;p->next=s;}}return(head);}main(){structnode*head;

inti,x;

printf("inputdatatocreat

linklist(endby<=0):\n");head=creat();

printf("thedataoflinklist:\n");print(head);

printf("insert:i,x=");scanf("%d%d",&i,&x);insert(head,i,x);

printf("thedataoflinklistafterinserted:\n");print(head);}10.5.4thedeleteoperationtolinklist[eg10.8]designafunctiondelete()，todeletethenodewhosedataisxinthelinklist。Commonsituation：Pre-deleted：After-deleted：

q=head;p=q->next;/*lookupthenodewhosevalueisx*/for(;p->num!=x&&p!=NULL;q=p,p=p->next);

if(p!=NULL)/*iffindit,ppointstothex,qpointstotheearlierone*/{q->next=p->next;free(p);}

132head5NULLhead

1325NULL4qpespescial：1、NULLlisthead=NULLerrorinformation2、deletetheheadnodepre-deleted：

after-deleted：3、nosuchnodeerrorinformationhead

4125NULL3head125NULL3structnode*delete_list(structnode*head,intx){structnode*p,*q;if(head==NULL)/*1、blanklist*/

printf("Error!Thelistisempty.\n");elseif(head->num==x)/*2、deletethefirstnode*/head=head->next;else {q=head;p=q->next;for(;p->num!=x&&p!=NULL;q=p,p=p->next); if(p==NULL)/*3、notexist*/

printf("Error!Thenumbeisnotexsist.\n");else{q->next=p->next;free(p);}/*deleteunheadednode*/ }return(head);}10.5.5colligatedexample：menuprogramdesigning/*=======sortedlink_list

operater=======*//*DesignedbySunQiaoping*/#include"stdio.h";#defineNULL0#defineLENsizeof(structnode)structnode{intnum;

structnode*next;};charmenu(void);voidprint(structnode*head);structnode*insert_sortedlist(structnode*head,intx);structnode*creat_sortedlist(void);structnode*delete_list(structnode*head,intx);main(){structnode*head=NULL;

inti,x,flag=1;charch;do{ch=menu();

clrscr();switch(ch){case'1':head=creat_sortedlist();break; case'2':printf("inputanumbertoinsert.x=");

scanf("%d",&x); head=insert_sortedlist(head,x);break; case'3':

printf("inputanumbertodelete.x=");

scanf("%d",&x); head=delete_list(head,x);break; case'4':print(head);break; case'0':flag=0;}}while(flag==1);}/*========menu========*/charmenu(void){charch;

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("Inputyourchoice(0,1,2,3,4):");

ch=getchar();

return(ch);}/*========insert========*/structnode*insert_sortedlist(structnode*head,intx){structnode*s,*p,*q;s=(structnode*)malloc(LEN);s->num=x;if(head==NULL)/*inserttoablanklist*/{head=s;s->next=NULL;}elseif(x<=head->num)/*inserttoheadoflist*/ {s->next=head;head=s;}else {q=head;p=q->next;/*lookuptheplacetoinsert*/ for(;p!=NULL&&x>p->num;q=p,p=p->next); s->next=p;/*insertafterqandaheadofp*/q->next=s; }return(head);}Pre-inserted：After-inserted：head

1368NULL44qs

136head8NULLp/*========creat========*/structnode*creat_sortedlist(void){structnode*head;

intx;

printf("inputdatatocreat

linklist(endby<=0):\n");head=NULL;while(1){scanf("%d",&x);if(x<=0)break;

head=insert_sortedlist(head,x);}return(head);}10.6introductiontounionandenum10.6.1union

1．conception

severalvariablesofdifferenttypeoccupythesamesegmentofstorage.

2．Definitionofunion

commonsituation：unionu_name {memberlist }；

eg.uniondata {inti; charch; floatf; };

Sameasdefinitionofstructuretype

3．DefinitionofSharingvariables(1)indirectdefinition

eg：uniondataun1,un2,un3；

(2)directdefiniton──definitevariableswhendefinitingtype

eg.union[data]{inti;charch;floatf;}un1,un2,un3;4．Thestoragelengthoccupiedbysharingvariables：thelengthoflongestmember5．Citingtosharingvariables──citingonebyone例如：un1.i、un1.ch、un1.f5．characteristic

(1)Systemusestheoverlayingtechonologytorealizememorysharingofthesharingvariables’members,soanytimethereisonlyonemembervaluetostoreandbetake.eg，ifun1.i=1,un1.ch=‘c’,un1.f=3.14，

un1.fisthevalidmember.(2)TheaddressofSharingvariableisthesameasthatofeverymember.eg