C語言學習課件第十一章

Chapter10Structures,Unions,Enumerations10.1Introduction10.2 StructureDefinitions結構體聲明10.3 InitializingStructures初始化結構體10.4 AccessingMembersofStructures10.5 UsingStructureswithFunctions函數中使用結構體10.6 ArrayofSructures

結構體數組10.7 typedef10.8 Example:High-PerformanceCardShufflingandDealingSimulation10.9Unions10.10EnumerationConstantsOutlineStructureDefinitions結構體聲明InitializingStructures初始化結構體AccessingMembersofStructures結構體變量的引用UsingStructureswithFunctions結構體與函數typedefArrayofSructures

結構體數組KeyPoints10.1IntroductionWhyneed“Structure”?Sofar,we’ddiscussedtwokindsofdata:Simple:char,int,long,double,etc.Scalar:array,pointer,etc.It’sinconvenientinsomeapplications:Seenextslidesforanexample10.1IntroductionWewanttorepresenttimeasyear/month/date:intf(){intyear1,year2,month,date;year1=2050;year2=2020;month=12;date=30;date++;/*Shouldweincreaseyear1oryear2?*/}Theproblemisthatthereisnologicalconnectionbetweenthem.Weneed“structure”!10.1IntroductionStructuresCollectionsofrelatedvariables(aggregates)underonename

多個相關變量的集合，且擁有同一個變量名CancontainvariablesofdifferentdatatypesCommonlyusedtodefinerecordstobestoredinfilesCombinedwithpointers,cancreatelinkedlists,stacks,queues,andtrees--將結構體和指針結合，可構造鏈表、棧、隊列、樹10.1IntroductionStructureStructureisaadvanceddatatypeinC.結構體是C中的高級數據類型Structureisamethodforgroupingaseveralrelateddatatypetogether.結構體是將一些相關聯的數據整合成整體的一種方法。Variableswithdifferenttypescanbegroupedinastructure。不同類型的變量可以組合在一個結構體內。Thesimplevariables:inta,b;a=20,b=85;-invidual

Array：floatgrade[20];

sametyperelatedgrade[0]grade[1]grade[2]grade[3]……10.1Introductionnumnamegrade1grade210Li90.5A11Liu80B12Wen88B….

intcharfloatchar

Howcanwedefinerelateddatathathavedifferenttype?

struct{intnum;charname[10];floatgrade1;chargrade2;};10.1IntroductionAllvariableswiththesametypescanbegroupedinaarray.wang98889887li87668367zhan78877561liu90768172zhao87817471Allvariableswithdifferenttypescanbegroupedinastructurenameagesexaddwang18m3-110li20f7-121liu17f7-212zhao18m3-222structuremembers(type,name)Structurevariables10.2StructureDefinitions1

32Astructureisacollectionofrelatedvariables,anynumberoftypeofvariablesmaybeincludedwithinit.Definingstructure,thendeclaringstructvariables.Definingstructureandstructvariables.structure’snamecanbeomittedkeywordstructStructuremembers

SturcturevariablesStructurevariablevalues10.2StructureDefinitionsDefiningstructure,thendeclaringstructvariables.先聲明結構體，再聲明結構體變量。

structstudent{intnum;charname[10];floatgrade1;chargrade2;};Structureisonlyasstructuretemplate,notoccupyingmemory,becausenoanyvariableyet.—聲明結構體時，并不占用內存空間。numnamegrade1grade2structname

{type1member1;type2member2;︰typenmembern;};（1）Definingstructure

10.2StructureDefinitionsstructdata{charname[20];intage;charaddress[30];longtelephone;}；Formal:structstruct_namestruct_variable_name;structdatawang;structdatali,zhang;（2）Declaringstructurevariable

nameageaddresstelephone10.2StructureDefinitionsname[20]

age20bytes2bytes30bytes4bytesaddresstelephonename[20]ageaddress[30]telephonestructdata{charname[20];intage;charaddress[30];longtelephone;};structdatawang;Afterdeclaration,computerwillassignmemoryunitstothem.–在結構體變量聲明后，計算機將給變量分配內存空間10.2StructureDefinitions

main(){charstr[20];

structdate{intyear,month,day;}today;

structaddress{charname[30],street[40],city[20],state[2];unsignedlongintzip;}wang;

printf("char:%d\t",sizeof(char));printf(“int:%d\t”,sizeof(int));printf("long:%d\t",sizeof(long));printf("float:%d\n",sizeof(float));printf("double:%d\t",sizeof(double));printf("str:%d\t",sizeof(str));printf("date:%d\t",sizeof(structdate));printf(“wang:%d\n”,sizeof(wang));}10.2StructureDefinitionsDefiningstructureandstructvariables.聲明結構體的同時，聲明結構體變量structname{type1member1;type2member2;︰typenmembern;}variable1,variable2…..;

structstudent{intnum;charname[20];charsex;intage;floatscore;charaddr[30];}stu1,stu2;numnamesexagescoreaddstu1stu210.2StructureDefinitionsstructure’snamecanbeomittedstruct{type1member1;type2member2;︰typenmembern;}variable1,variable2…..;

struct{intnum;charname[20];charsex;intage;floatscore;charaddr[30];}stu1,stu2;numnamesexagescoreaddr201wangM2095Zhongguancunroad202liF1980GuangdaGarden10.3InitializingStructures

structstudent{intnum;charname[20];charsex;intage;charaddr[30];}stu1={112,“WangLin”,‘M’,19,“200BeijingRoad”};

structstudent{intnum;charname[20];charsex;intage;charaddr[30];}stu1;stu1={112,“WangLin”,‘M’,19,“200BeijingRoad”};Howtousethesevalues?10.4AccessingMembersofStructuresstud1.grade1=95;stud1.grade2=‘A’;where“.”iscalled

memberoperator.struct_var_name.member_name

struct{intnum;charname[10];floatgrade1;chargrade2;}stud1,stud2,stud3;scanf(“%s,%f,%c,”,&,&stud2.grade1,&stud2.grade2);printf(“%s,%f,%c,”,,stude2grade1,stude2grade2);10.4AccessingMembersofStructures/*assignment*/main(){struct{charinitial;/*lastnameinitial*/intage;/*childsage*/intgrade;/*childsgradeinschool*/}boy,girl;boy.initial='R';boy.age=17;boy.grade=75;

girl.age=boy.age-1;/*sheisoneyearyounger*/girl.grade=82;girl.initial='H';printf("%cis%dyearsoldandgotagradeof%d\n",girl.initial,girl.age,girl.grade);printf("%cis%dyearsoldandgotagradeof%d\n",boy.initial,boy.age,boy.grade);}10.4AccessingMembersofStructuresOworkaddressHomeaddresspostaddrtelpostaddrtelstructaddress{intpostcharaddr[100];chartel[20];};structpersonal{charname[20];structaddressworkaddr;structaddresshomeaddr;};struct_var_name.out_mem.inner_mem10.4AccessingMembersofStructuresmain(){structdate{/*structuretypedate*/intyear,month,day;

};structdatetoday;/*stru-vartoday*/printf("Entertodaydate:");scanf(“%d%d%d”,&today.year,&today.month,&today.day);printf(“%d.%d.%d\n”,today.year,today.month,today.day);}date&today.daytoday.day10.4AccessingMembersofStructuresExercise:

structstudent{intnocharname[20];charsex;struct

{intyear;intmonth;intday;}birth;};structstudents;A)year=1982month=11day=11B)birth.year=1982,birth.month=11birth.day=11C)s.year=1982s.month=11s.day=11D)s.birth.year=1982s.birth.month=11s.birth.day=11

Ifthebirthdayis“11/11

/82”，whichisthecorrectassignmentstatement?10.5UsingStructuresWithFunctionsPassingstructurestofunctionsPassentirestructureOr,passindividualmembersBothpasscallbyvalueTopassstructurescall-by-reference

PassitsaddressPassreferencetoitTopassarrayscall-by-valueCreateastructurewiththearrayasamemberPassthestructure10.5UsingStructuresWithFunctionsStructurememberasargumentstructxscj{char*xh;floatcj[2];floatav;};main(){structxscjxs={"01",70,80},inti;xs.av=ave(xs.cj[0],xs.cj[1]);printf("%s,%5.1f,%5.1f,%5.1f\n",xs.xh,xs.cj[0],xs.cj[1],xs.av);}}ave(floatx,floaty){floata;a=(x+y)/2.0;returna;}01,70.0,80.0,75.002,78.0,67.0,72.503,56.0,78.0,67.004,90.0,80.0,85.010.5UsingStructuresWithFunctionsStructureasargumentstructxscj{char*xh;floatcj[2];floatav;};voidf1(structxscjtj);main(){structxscjxs={"01",70,80,0};f1(xs);}

voidf1(structxscjtj){tj.av=(tj.cj[0]+tj.cj[1])/2.0;printf("%s,%5.1f,%5.1f,%5.1f\n",tj.xh,tj.cj[0],tj.cj[1],tj.av);}output01,70.0,80.0,75.010.6ArrayofSructures

DefinitionForm1

structstudent{intnum;charname[20];charsex;intage;};structstudentstu[30];Form2

structstudent{intnum;charname[20];charsex;intage;}stu[30];Form3

struct{intnum;charname[20];charsex;intage;}stu[30];Array–groupseveralrelatedvariableswiththesametype,storeinsequence30studentsInoneclassThetypeisstructure10.6ArrayofSructures

TherelationshipbetweenstructureandarrayArrayisamemberofastructureAnarraywhichmembersareallstructurevariablenumNameScore[0]Score[1]101wang9098110zhan8775struct{intnum;

charname[20];floatscore[2];}stu1,stu2;numNameScore[0]Score[1]101wang9098110zhan8775struct{intnum;

charname[20];floatscore[2];}stu[2];10.6ArrayofSructures

Initualizationstructstud{intxh;......};structstudxscj[3]＝{{},{},{}};

OR：structstud{intxh;......}xscj[3]＝{{},{},{}};Datainonearray10.6ArrayofSructures

Accessmembersofstructurearraymain(){structxscjxs[4]={{"01",70,80},{"02",78,67},{"03",56,78},{"04",90,80}};inti;for(i=0;i<4;i++){xs[i].av=(xs[i].cj[0]+xs[i].cj[1])/2.0;printf("%s,%5.1f,%5.1f,%5.1f\n",xs[i].xh,xs[i].cj[0],xs[i].cj[1],xs[i].av);}}structxscj{char*xh;floatcj[2];floatav;};structurearraymemberofstructurememberofthearrayoutput01,70.0,80.0,75.002,78.0,67.0,72.503,56.0,78.0,67.004,90.0,80.0,85.010.6ArrayofSructures

Afterdeclaration,howtooutput‘M’?structperson{charname[9];

intage;};structpersonclass[10]={“Wang”,17,“Zhang”,19,“Ming”,18,“Liu”,20};A)printf(“%c\n”,class[3].name);B)printf(“%c\n”,class[3].name[1]);C)printf(“%c\n”,class[2].name[1]);D)printf(“%c\n”,class[2].name[0]);MemberofarrayMemberofstructurearray10.7typedeftypedefCreatessynonyms(aliases)forpreviouslydefineddatatypesUsetypedeftocreateshortertypenamesExample:typedefstructCard*CardPtr;DefinesanewtypenameCardPtrasasynonymfortypestructCard*typedefdoesnotcreateanewdatatypeOnlycreatesanalias10.7typedefDefinitethealiasofstructurestructdateasDATE.structdate{intyear,month,day;};typedefstructdateDATE;DATAt,*p;

equalto：typedefstructdate

{intyear,month,day;}DATE;DATAt,*p;Onlycreatesanalias.10.7typedefDemonstration（說明）：

Todefiniteanaliastoaexistvariableusingtypedefwon’tcreatanewtype.Differencebetweentypedefand#define.typedefisdisposingwhencompiling；#defineisdispoingwhenpreprocessing，asacounterpart10.8Example統(tǒng)計十佳運動員選票，在統(tǒng)計之前要將預選的運動員名字賦給相應的name數組，同時將每個人的選票計數器清零。structports｛char*name;intcount;｝x[]=｛"LiNing",0,"LangPing",0,"ZhuJianHua",0,"LanJuJie",0｝;main()｛inti;for(i=0,i<=3;i++)printf("%s:%d＼n",x[i].name,x[i].count);

｝10.8Example簡單的加密程序?？啥x一個結構table的成員in，存入輸入的字符，out輸出加密后的字符。輸入(in)：abcdefghijkwxy輸出(out)：cdfahikxywbgje#include〈stdio.h〉structtable｛charin;charout;};structtabletrans[]={’a’,’c’,’b’,’d’,’c’,’f’,’d’,’a’,’e’,’h’,’f’,’i’,’g’,’k’,’h’,’x’,’i’,’y’,’j’,’w’,‘k’,’b’,’v’,’g’,’x’,’j’,’y’,’e’｝;

10.8Examplemain()｛charch;intstrlong,i;strlong=sizeof(trans)/sizeof(structtable);while((ch=getchar())!=‘\n’){for(i=0;trans[i].in!=ch&&i<strlong;i++); if(i<strlong)putchar(trans[i].out);elseputchar(ch);｝}10.9UnionsunionMemorythatcontainsavarietyofobjectsovertimeOnlycontainsonedatamemberatatimeMembersofaunionsharespaceConservesstorageOnlythelastdatamemberdefinedcanbeaccesseduniondeclarationsSameasstructunionNumber{intx;floaty;};unionNumbervalue;10.9UnionsValidunionoperationsAssignmenttounionofsametype:=Takingaddress:&Accessingunionmembers:.Accessingmembersusingpointers:->1.Defineunion1.1Initializevariables2.Setvariables3.Print 1 /* 2

Anexampleofaunion*/ 3 #include<stdio.h> 4 5 unionnumber{ 6

intx; 7

doubley; 8 }; 9 10 intmain() 11 { 12

unionnumbervalue; 13

14

value.x=100; 15

printf("%s\n%s\n%s%d\n%s%f\n\n", 16 "Putavalueintheintegermember", 17 "andprintbothmembers.", 18 "int:",value.x, 19 "double:\n",value.y); 20

21

value.y=100.0; 22

printf("%s\n%s\n%s%d\n%s%f\n", 23 "Putavalueinthefloatingmember", 24 "andprintbothmembers.", 25 "int:",value.x, 26 "double:\n",value.y); 27

return0; 28 }

P:100double:-92559592117433136000000000000000000000000000000000000000000000.00000

P:0double:100.000000ProgramOutput10.10EnumerationConstantsEnumerationSetofintegerconstantsrepresentedbyidentifiersEnumerationconstantsarelikesymbolicconstantswhosevaluesareautomaticallysetValuesstartat0andareincrementedby1Valuescanbesetexplicitlywith=NeeduniqueconstantnamesExample:enumMon