版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领
文档简介
ObjectivesToknowwhyneedsoperatoroverloadingToknowwhatoperatorfunctionsareTo
be
abletodefinebinaryoperatorfunctionTobeabletodefineunaryoperatorfunction01Introduction03BinaryOperatorOverloading02OperatorFunctions04UnaryOperatorOverloading05CaseStudy01IntroductiontoOperatorOverloadingIntroductiontoOperatorOverloadingForexample,built-inoperators,+,-,=,<=,[],>>,<<2+3,3.4+5.4,‘a’+’b’Usingthesamenameforoperationsondifferenttypesisknownasoverloading.Operatoroverloading:Redefinemostofthebuilt-inoperatorsavailableforoperationson
user-definedtypes(abstractdatatypes).class
MyInteger{public:MyInteger(int=0);intget()const;MyIntegeraddition(const
MyInteger&);MyIntegermultiplication(const
MyInteger&);private:intvalue;};WhyNeedsOperatorOverloading?MyIntegervalue:int+MyInteger(int=0)+~MyInteger()+addition(constMyInteger&):MyInteger+multiplication(constMyInteger&):MyInteger+get():intconstCaseStudy1DefineaMyIntegerclasswithavalueattribute.Youneeddothefollowingtask:addtwoMyIntegerobjectsmultiplytwoMyIntegerobjectsWhyNeedsOperatorOverloading?intmain(){MyIntegeri1(10),i2(25);cout<<i1.get()<<
","
<<i2.get()<<endl;MyIntegeri3;i3=i1.addition(i2);cout<<i3.get()<<endl;i3=i1.multiplication(i2);cout<<i3.get()<<endl;return0;}i3=i1+i2;i3=i1*i2;MyInteger
MyInteger::addition(const
MyInteger&myint){return
MyInteger(this->value+myint.value);}MyInteger
MyInteger::multiplication(const
MyInteger&myint){return
MyInteger(this->value*myint.value);}MyInteger::MyInteger(int
v):value(v){}int
MyInteger::get()const{returnvalue;}MyInteger::~MyInteger(){}MyIntegervalue:int+MyInteger(int=0)+~MyInteger()+addition(constMyInteger&):MyInteger+multiplication(constMyInteger&):MyInteger+get():intconstWhyNeedsOperatorOverloading?Definingoperatorsforuser-definedtypeallowsaprogrammertoprovideamoreconventionalandconvenient
notationformanipulatingobjects.MyIntegeri3;i3=i1+i2;i3=i1*i2;intn;cin>>n;cout<<n;class
MyInteger{public:MyInteger(int=0);intget()const;MyInteger
operator+(const
MyInteger&);MyInteger
operator*(const
MyInteger&);private:intvalue;};OperatoroverloadingFunctionMyInteger
MyInteger::operator+(const
MyInteger&myint){return
MyInteger(this->value+myint.value);}MyInteger
MyInteger::operator*(const
MyInteger&myint){return
MyInteger(this->value*myint.value);}intmain(){MyIntegeri1(10),i2(25);cout<<i1.get()<<
","
<<i2.get()<<endl;MyIntegeri3;i3=i1+i2;//i3=i1.addition(i2);cout<<i3.get()<<endl;i3=i1*i2;//i3=i1.multiplication(i2);cout<<i3.get()<<endl;return0;}WhyNeedsOperatorOverloading?MyIntegervalue:int+MyInteger(int=0)+~MyInteger()+operator+(constMyInteger&):MyInteger+operator*(constMyInteger&):MyInteger+get():intconst02OperatorFunctionsOperatorFunctionsMyIntegeroperator+(constMyInteger&myint);returningtypeoperatorfunctionnameparameterlistForexample,Tooverloadanoperator,youmustdefineafunction,calledoperatoroverloadingfunction(operatorfunction).returning-typeoperatorSymbol(parameter
list)SyntaxtodefineanoperatorfunctionoperatorfunctionnameOperatorFunctionsThefollowingoperatorscanbeoverloaded.Thefollowingoperatorscannotbeoverloaded.::---scoperesolution,e.g.Date::print();?:---ternaryconditional(if-then-else),e.g.x>y?x:y;.---memberselection,e.g.day.print();.*---memberselectionthroughpointertomember,e.g.student.*nameOperatorFunctionsYoucannotoverloadalloperators.Youcannotcreateanewoperator.Onlyexistingoperatorcanbeoverloaded.Youtrytokeepthemeaningofhowtheoperatorworkswithbuilt-intypes.Operatorfunctionscanbememberfunctionsofclassesornon-member
functions.
03BinaryOperatorOverloadingBinaryOperatorsForexample,+,-,==,!=,&&Abinaryoperatorisanoperatorthatoperatesontwooperandsandmanipulatesthemtoreturnaresult.HowtoOverloadBinaryOperatorsForanybinaryoperator@,
aa@bb
MyInteger
MyInteger::operator+(MyInteger&i);MyInteger
operator+(MyInteger&i1,MyInteger&i2);Object’snames,user-definedtypeintmain{MyIntegeri1(10),i2(25),i3;i3=i1+i2;i3=i1*i2;}SyntaxtodefineabinaryoperatorfunctionIfanoperatorfunctionisdefinedasamemberfunction,
ittakesoneparameter.TherearetwowaystodefineanoperatorfunctionIfanoperatorfunctionisdefinedasanon-memberfunction,
ittakestwoparameters.aa.operator+(bb)operator+(aa,bb)HowtoOverloadBinaryOperatorsclass
MyInteger{public:MyInteger(int
v):value(v){}MyIntegeroperator+(MyInteger&);friend
MyIntegeroperator-(MyInteger&,MyInteger&);intget()const{returnvalue;}private:intvalue;};memberfunctionnon-memberfunctionintmain(){MyIntegera(13);MyIntegerb(12);MyIntegerc=b;//copyconstructora=b+c;b=b+c-a;cout<<a.get()<<b.get();return0;}MyInteger
MyInteger::operator+(MyInteger&i){MyIntegertemp(0);temp.value=this->value+i.value;returntemp;}MyIntegeroperator-(MyInteger&i1,MyInteger&i2){MyIntegertemp(0);temp.value=i1.value-i2.value;returntemp;}a=b.operator+(c)b=operator-(b.operator+(c),a)04UnaryOperatorOverloadingUnaryOperatorsForexample,++a,--a,a--,a++,a−(−b),~a,!aAnunaryoperatorisanoperatorthatactsuponasingleoperandtoproduceanewvalue.HowtoOverloadUnaryOperatorsForanyprefixunaryoperator@@aaDefinitionofprefix
increment/decrementoperatorsObject’sname,user-definedtypeintmain{MyIntegeri1(10),i2(25);++i1;--i2;cout<<(++i1).get()<<endl;}MyInteger&MyInteger::operator++();MyInteger
operator--(MyInteger&);SyntaxtodefineanunaryoperatorfunctionIfanoperatorfunctionisdefinedasamemberfunction,
itdoesnottakeanyparameter.TherearetwowaystodefineanoperatorfunctionIfanoperatorfunctionisdefinedasanon-memberfunction,
ittakesoneparameter.aa.operator++()operator--(aa)PrefixUnaryOperatorsclass
MyInteger{public:MyInteger(int);intget()const;MyInteger&operator++();//memberfunctionfriend
MyInteger
operator--(MyInteger&);//non-memberfunctionprivate:intvalue;};intmain(){MyIntegeri1(10),i2(25);cout<<i1.get()<<
","
<<i2.get()<<endl;cout<<(++i1).get()<<endl;cout<<(--i2).get()<<endl;return0;}MyInteger&MyInteger::operator++(){
this->value++;
return*this;}(i1.operator++()).get()(operator--(i2)).get()MyInteger
operator--(MyInteger&myint){
myint.value--;return
myint;}PrefixunaryoperatorsWhytoreturnthethispointer?PostfixUnaryOperatorsForanypostfixunaryoperator@aa@Definitionofpostfixincrement/decrementoperatorsObject’sname,user-definedtypeintmain(){MyIntegeri1(10),i2(25);i1++;i2++;cout<<(i1++).get()<<endl;}SyntaxtodefineanunaryoperatorfunctionIfanoperatorfunctionisdefinedasamemberfunction,
itdoesnottakeanyparameter,butidentifierint.TherearetwowaystodefineanoperatorfunctionIfanoperatorfunctionisdefinedasanon-memberfunction,
ittakesoneparameterandidentifierint.MyInteger
MyInteger::operator++(int);MyInteger
operator--(MyInteger&,int);Note:intisadummyparameteraa.operator++(int)operator--(aa,int)PostfixUnaryOperatorsintmain(){MyIntegeri1(10),i2(25);cout<<i1.get()<<
","
<<i2.get()<<endl;cout<<(i1++).get()<<endl;cout<<i1.get()<<endl;cout<<(i2--).get()<<endl;cout<<i2.get()<<endl;return0;}class
MyInteger{public:MyInteger(int);intget()const;MyInteger
operator++(int);//memberfunctionfriend
MyInteger
operator--(MyInteger&,int);private:intvalue;};(i1.operator++(int)).get()(operator--(i2,int)).get()postfixunaryoperatorsMyInteger
MyInteger::operator++(int){MyIntegertemp(0)=*this;this->value++;returntemp;}MyInteger
operator--(MyInteger&myint,int){MyIntegertemp(0)=myint;myint.value--;returntemp;}05CaseStudyCaseStudyGivenatestprogramasfollows.DefineaComplexclassaccordingtothetestprogram.a+biComplexreal:doubleimag:double+Complex(double=0,double=0)+~Complex()+Complex(constComplex&)+operator+(constComplex&):Complex+operator=(constComplex&):Complex&+operator++():Complex&+operator++(int):Complex+print():voidconstintmain(){Complexc1(2.1,4.5),c2(3.4,5.6);c1.print();c2.print();Complexc3=c1+c2;c3.print();c1=c3;c1.print();(++c3).print();(c3++).print();c3.print();return0;}DefinitionoftheComplexclassWhendoyouneedtopassavalueorareferencetoanoperatorfunction?Whendoyouneedtoreturnavalueorareferencefromanoperatorfunction?class
Complex{public:Complex(double
r=0,double
i=0);//defaultconstructorComplex(const
Complex&);//copyconstructorComplex
operator+(Complex&);//operator+Complex&operator=(Complex&);//operator=Complex&operator++();//prefixoperator++friend
Complex
operator++(Complex&,int);//postfixoperator++voidprint()const;private:doublereal,imag;};Complexreal:doubleimag:double+Complex(double=0,double=0)+~Complex()+Complex(constComplex&)+operator+(constComplex&):Complex+operator=(constComplex&):Complex&+operator++():Complex&+operator++(int):Complex+print():voidconstBinaryandUnaryOperatorFunctionsComplex
Complex::operator+(Complex&c){return
Complex(this->real+c.real,this->imag+c.imag);}class
Complex{public:Complex(double
r=0,double
i=0);//defaultconstructorComplex(const
Complex&);//copyconstructorComplex
operator+(Complex&);//operator+Complex&operator=(Complex&);//operator=Complex&operator++();//prefixoperator++friend
Complex
operator++(Complex&,int);//postfixoperator++voidprint()const;private:doublereal,imag;};Complex&Complex::operator++(){this->real++;this->imag++;return*this;}prefixComplex
operator++(Complex&c,int){Complextemp=c;c.real++;c.imag++;returntemp;}postfixComplex&Complex::operator=(Complex&c){this->real=c.real;this->imag=c.imag;return*this;}Complex::Complex(const
Complex&c){this->real=c.real;this->imag=c.imag;}ThinkOverintmain(){Complexc1(2.1,4.5),c2(3.4,5.6);c1.print();c2.print();Complexc3=c1+c2;c3.print();c1=c3;c1.print();(++c3).print();(c3++).print();c3.print();return0;}Whatisthedifferencebetweenthesetwostatements?SummaryWhyneedsoperatoroverloading?Whatdooperatorfunctionsmean?OverloadingbinaryoperatorsAbinaryoperatorcanbedefinedbyeitheranon-staticmemberfunctiontakingoneparameteroranon-memberfunction
takingtwoparameters.OverloadingunaryoperatorsPrefix:Aunaryoperatorcanbedefinedbyeitheranon-staticmemberfunctionwithoutparameteroranon-memberfunction
withoneparameters.Postfix:Aunaryoperatorcanbedefinedbyeitheranon-staticmemberfunctionwithoutparameterbutintoranon-memberfunction
withoneparametersbutint.ObjectivesTobeabletodefinemixedarithmeticofuser-definedtypesandbuilt-intypesTobeabletooverloadcombinatorialoperatorsTo
understandhowtoconvertobjectsfromuser-definedtypestobuilt-intypes01CombinatorialOperators03TypeConversion02MixedArithmetic04CaseStudy:Operators<<and>>01OverloadingCombinatorialOperatorsCombinatorialOperatorsForabuilt-intype,forexample,aisaninteger,ifa+=
5,itmeansa=a+5.Forexample,complexc1,c2;c2+=c1;Themeaningsofsomebuilt-inoperatorsaredefinedtobeequivalenttosomecombinationofotheroperatorsonthesameparameters.Canthecombinationaloperatorsworkontheuser-definedtypes?OverloadingCombinatorialOperatorsCaseStudy1Accordingtothetestprogram.Definethemeaningofoperator+=.intmain(){complexc1(20.3,11.3);complexc2;c2+=c1;c2.print();return0;}class
complex{public:complex(double
r=0.0,double
i=0.0):real(r),imag(i){}complexoperator+(complex&c);complex&operator=(const
complex&c);complex&operator+=(complex&c);voidprint()const;private:
doublereal,imag;};OverloadingCombinatorialOperatorscomplex
complex::operator+(complex&c){complextemp;temp.real=this->real+c.real;temp.imag=this->imag+c.imag;returntemp;}complex&complex::operator=(const
complex&c){if(this!=&c){this->real=c.real;this->imag=c.imag;}return*this;}complex&complex::operator+=(complex&c){*this=*this+c;return*this;}complex&complex::operator+=(complex&c){this->real+=c.real;this->imag+=c.imag;return*this;}02MixedArithmeticcomplexc1,c2(3.0,4.0);doubled=5.2;c2=c1+d;c2=d+c1;MixedArithmeticdouble(abuilt-intype)complex(user-definedtype)c1+dMemberfunction:c1.operator+(d)Non-memberfunction:operator+(c1,d)d+c1Memberfunction:d.operator+(c1)Non-memberfunction:operator+(d,c1)Mixedauser-definedtypes
withabuilt-intypeAnoperatorfunctioncanbedefinedforthemixedarithmeticofauser-definedtypeandbuilt-intype.MixedArithmeticAnoperatorfunctionmusteitherbememberofauser-definedtypesornon-membertakingatleastoneparameterofauser-definedtypes.Thisensuresthatausercannotchangethemeaningofanexpression.
MemberfunctionNon-memberfunctionintmain(){complexc1,c2(3.0,4.0);doubled=5.2;c2=c1+d;c2=d+c1;return0;}c2=c1.operator+(d)c2=operator+(d,c1)HowtoDefineMixedArithmeticclass
complex{public:complex(double
r=0.0,double
i=0.0):real(r),imag(i){}complex
operator+(double);friend
complex
operator+(double,complex&);private:doublereal,imag;};complex
complex::operator+(double
dd){return
complex(this->real+dd,this->imag);}complex
operator+(double
dd,complex&c){return
complex(c.real+dd,c.imag);}intmain(){complexc1,c2(3.0,4.0);doubled=5.2;c2=c1+d;c2=d+c1;return0;}03TypeConversionTypeConversioninti=5,j;doublea=3.4;j=i+a;doubleb=i/2;Forabuilt-intype,inti=5,j;doublea=3.4;j=i+(int)a;doubleb=(double)i/2;inti=5,j;doublea=3.4;j=i+static_cast<int>(a);doubleb=static_cast<double>(i)/2;C-styleC++styleUsingstatic_castoperatorinC++TypeConversionForauser-definedtypecomplexc1;doublea,b;b=c1+a;Thecompiler
cannotautomaticallyknowhowtoconvertuser-definedtypesintobuilt-intypesorbuilt-intypestouser-definedtypes.complexc1;complex
c2=
2.4;TypeConversionTherearetwowaysfortypeconversion:Fromabuilt-intypetoauser-definedtype.Fromauser-definedtypetoabuilt-intype.
Ifaclasshasaconstructorwhichcanbecalledwithasingleargument,thenthisconstructorbecomesconversionconstructorbecausesuchaconstructorallowsautomaticconversiontotheclassbeingconstructed.
Fromabuilt-intypetoauser-definedtypeTypeConversionclass
complex{public:complex(double
r,double
i):real(r),imag(i){}private:
doublereal,imag;};intmain(){complexc1(20.3,11.3);complexc2=10.5;return0;}complex::complex(double
r){real=r;imag=0.0;}complex(double);ConversionconstructorConversionConstructorsareconstructorsthatconverttypesofitsparameterintoatypeoftheclass.Thecompilerusestheseconstructorstoperformimplicitclass-typeconversions.Built-intypeUser-definedtypeTypeConversionTheconversionconstructorcannotspecify:animplicitconversionfromauser-definedtypetoabuilt-intype.Forexample,complex(classtype)int2.aconversionfromanewclasstoapreviouslydefinedclass(withoutmodifyingthedeclarationfortheoldclass).Forexample, complex(classtype)Date(classtype)TypeConversionoperatorT()constFromauser-definedtypetoabuilt-intypeSyntaxtodefineatypeconversionoperator
Atypeconversionoperatorinaclasscanconvertthe
classtypetoTtype
(built-intypesoruser-definedtypes).Itmustbedefinedasamemberfunction.TypeConversionclass
complex{public:complex(double
r,double
i):real(r),imag(i){}complex(doubler);operator
double()const;operator
int()const;voidprint()const;private:doublereal,imag;};complex::operator
double()const{returnreal;}complex::operator
int()const{return
static_cast<int>(real);}intmain(){complexc1=5.4;c1.print();doubled=(double)c1+3.4;cout<<d<<endl;intm=static_cast<int>(c1)+10;cout<<m<<endl;return0;}complex(classtype)Built-intypeTypeConversionclass
Test1{public:Test1(int
s){a=s;}
intget()const{returna;}private:
inta;};class
Test2{public:Test2(int
i):x(i){}
operator
Test1(){return
Test1(x);}
intget()const{returnx;}private:
intx;};Test2(class)->Test1(class)intmain(){
Test2t2Obj(20);cout<<
"Test2'sobject:"
<<t2Obj.get()<<endl;
Test1t1Obj_0=40;//willcompilecout<<
"Test1'sobject:"
<<t1Obj_0.get()<<endl;
Test1t1Obj_1=(Test1)t2Obj;//conversion->copycout<<
"Test1'sobject:"
<<t1Obj_1.get()<<endl;
return0;}04CaseStudy:OverloadingOperators<<and>>CaseStudy:OverloadingOperators<<and>>class
complex{public:complex(double
r=0,double
im=0):real(r),imag(im){}friend
ostream&operator<<(ostream&,complex&);friend
istream&operator>>(istream&,complex&);private:doublereal,imag;};intmain(){complexc1;cin>>c1;cout<<c1<<endl;return0;}Theseoperatorsmustbeoverloadedasa
globalfunction.Andifwewanttoallowthemtoaccessprivatedatamembersoftheclass,wemustmakethem
friend.
istream&operator>>(istream&in,complex&c){in>>c.real>>c.imag;
return
in;}ostream&operator<<(ostream&out,complex&c){out<<“Thecomplexis"<<c.real<<""<<c.imag<<endl;return
out;}SummaryUnderstandhowtooverloadcombinatorialoperatorsUnderstandhowtoimplementmixedarithmeticUnderstandtypeconversionsObjectivesTounderstandclasshierarchyandinheritanceTobeabletoderivenewclassesfromexistingclassesTo
beabletodefineconstructorsanddestructorsofderivedclasses01ClassHierarchiesand
Inheritance03Constructorsand
DestructorsofDerivedClasses02InheritanceandDerivedClasses04Inheritanceand
Composition01ClassHierarchiesandInheritanceClassHierarchyTherearedifferentpositionsofemployeesinacompany,i.e.secretary,managerandengineer.ThethreeclassesaredesignedbythefollowingUMLdiagram.Secretary-name:string-ID:intdepartment:stringduty:string+
print():voidconst+sendDoc():
voidManager-name:string-ID:intdepartment:stringresponsibility:string+print():voidconst+management():voidEngineer-name:string-ID:intdepartment:stringworkType:string+print():voidconst+design():voidDataabstraction1.Data–name,ID,departmentsecretary:dutymanager:responsibilityengineer:worktype2.Functions(operations)printsecretary:senddocuments
manager:managementengineer:designCaseStudy1ClassHierarchySecretary-duty:string+sendDoc():
voidManager-responsibility:string+management():voidEngineer-workType:string+design():voidEmployee-name:string-ID:intdepartment:string+print():voidconstForexample,3Dgeometric-cube,cuboidAnimal-cat,dog,cowPerson-student,teacherAbstractcommonfeaturesandputtheminaclass.Aclasshierarchyrepresentsasetofhierarchicallyorganizedconcepts.Someclassedarederivedfromcommonclasses.Suchasetofrelatedclassesistraditionallycalledaclasshierarchy.Inheritance(继承)Inheritanceisoneofthemostimportantfeatureintheobject-orientedprogramming,enablingyoutoorganizeclassesinahierarchicalform.Anewclasscaninherittheexistingclass’sdatamembersandmemberfunctionsandaddmembersofitsown.Thisprocessofcreatinganewclassfromanexistingclassisknownasinheritance.Themainadvantageofinheritanceisthereusabilityofthecode.Inheritanceallowswell-testedcodetobereusedandenableschangestomakeonceandaffectallrelevantplaces.
TypeofInheritanceTreestructureofclasshierarchyLatticestructureofclasshierarchySingleinheritanceandmultilevelinheritanceMultipleinheritanceandhybridinheritance02InheritanceandDerivedClassesHowtoImplementInheritanceManager-name:string-ID:intdepartment:string-responsibility:string+print():voidconst+management():voidEmployee-name:string-ID:intdepartment:string
+print():voidconstclass
Employee{public:intprint()const;private:stringname;intID;stringdepartment;};class
Manager{public:voidmanagement();private:Employeeemp;
stringresponsibility;};
XDoesamanagerhaveanemployee??AmanagerisanemployeeHowtoImplementInheritanceAmanagerisanemployeeclass
Employee{public:intprint()const;private:stringname;intID;stringdepartment;};class
Manager:public
Employee{public:voidmanagement();private:stringresponsibility;};derivedclass(childclass)-anewclassbaseclass(parentclass)–anexistingclassManager-responsibility:string+management():voidEmployee-name:string-ID:intdepartment:string+print():voidconstThe
arrow
pointingupwardfromclassManagertoclassEmployeeClassManagerinheritsdatamembersandmemberfunctionsfromclassEmployee.InheritanceItisamechanism
whichonenewclassisabletoinherittheproperties(thedataandoperations)froman
existingclass.InheritanceisanimportantfeatureinOOP.Itprovidesawayforobjectstodefinerelationshipseachother.Theadvantageofinheritanceissoftwarereusability.HowtoDefineDerivedClassesclassderived_class:
publicbase_class{/*...*/};baseclassnameaccessspecifierderivedclassnameSyntaxtodefineaderivedclassclass
Employee{public:Employee(string,int,
string);intprint()const;private:stringname;intID;stringdepartment;};class
Manager:public
Employee{public:Manager(string,int,string,string);voidmanagement()const;private:stringresponsibility;};stringname;intID;stringdepartment;voidprint()const;DerivedClassesForexample,aManagerisanEmployee,sowecanwriteManagerm;Employeee=m;//okHowever,anEmployeeisnotnecessarilyaManager,soanEmployeecannotbeusedasaManager.
Employeee;Managerm=e;//errorRelationshipbetween
baseclassesandderivedclasses“is-a”Thederivedclassisabaseclass.Sothederivedclasscanbeusedasabaseclass.03ConstructorsandDestructorsofDerivedClassesDerivedClasses’Constructorsderived_constructor_name(parameters):base_constructor_name(parameters){...}InitializationlistAderivedclassinheritseverymemberofitsbaseclassexcept:itsconstructorsanddestructorsitsoverloadedoperator(=)itsfriendsSyntaxtodefinethe
constructor
of
aderivedclassDerivedClasses’ConstructionResult:thisisabaseclassthisisabaseclassthisisaderivedclassConstructorwithoutparametersclass
Employee{public:Employee(){cout<<"thisisabaseclass\n";}};class
Manager:public
Employee{public:Manager():Employee(){cout<<"thisisderivedclass.\n";}};intmain(){Employeeem;Managerma;}DerivedClasses’ConstructionConstructorswithparametersclass
Employee{public:Employee(string
n,int
no){name=n;No=no;cout<<name<<"isanemployee.\n";}private:
stringname;
intNo;};class
Manager:public
Employee{public:Manager(string
n,int
no,string
rs):Employee(n,no){cout<<"Heisalsoamanager.\n";responsibility=rs;}private:stringresponsibility;};intmain(){Employeeem("Tom",1);Managerma("Jerry",2,"sign");}Result:Tomisanemployee.Jerryisanemployee.Heisalsoamanager.DerivedClasses’DestructorsThedestructorofaderivedclassisusedtocleanupandreleasememory.Thedefinitionofderivedclass’sdestructoristhesameasitsbaseclass’s.class
Manager:public
Employee{public:Manager(string
n,int
no,string
rs):Employee(n,no){cout<<"Heisalsoamanager.\n";responsibility=rs;}~Manager(){cout<<"Managerisdestroyed.\n";}private:stringresponsibility;};DerivedClasses’ConstructorandDestructorclass
Employee{public:Employee(string
n,int
温馨提示
- 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
- 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
- 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
- 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
- 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
- 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
- 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
评论
0/150
提交评论