解析C例題代碼第3章例題

1、精選優(yōu)質(zhì)文檔-傾情為你奉上第3章例題【例3-1】/employee2.h#include <iostream>#include <string>using namespace std;class Employee /定義Employee類public:Employee(); /構(gòu)造函數(shù)的聲明 void Setname(string); /設(shè)置姓名函數(shù) void Setpay(float pay); /設(shè)置工資函數(shù) string Getname();/提取姓名函數(shù)void Display();/顯示信息函數(shù)protected:string name; /姓名int no;

2、 /編號float salary; /月工資 static int maxno; /靜態(tài)數(shù)據(jù)成員，表示員工編號基數(shù);/employee2.cpp#include "employee2.h"int Employee:maxno=1000; /靜態(tài)數(shù)據(jù)成員初始化Employee:Employee() /構(gòu)造函數(shù)的實現(xiàn) no=+maxno;void Employee:Setname(string namep) /設(shè)置姓名函數(shù)，指針作函數(shù)參數(shù) name=namep;void Employee:Display()/顯示信息函數(shù) cout<<"編號為："

3、<<no<<"，"<<"本月工資為："<<salary<<endl;string Employee:Getname()/提取姓名函數(shù)return name;void Employee:Setpay(float pay)/設(shè)置工資函數(shù)salary=pay;/example3_34.cpp#include "employee2.h"int main() Employee employy4; /創(chuàng)建對象數(shù)組float pay;string nameptr;/字符數(shù)組int i;fo

4、r(i=0;i<4;i+)cout<<"請輸入下一個員工的姓名："cin>>nameptr;employyi.Setname(nameptr);cout<<"請輸入員工的月工資："cin>>pay;employyi.Setpay(pay);for(i=0;i<4;i+)cout<<employyi.Getname()<<"的"employyi.Display();return 0;【例3-2】/example3_2.cpp#include <io

5、stream>using namespace std;void f1()int a=1,b=2; static int c; a+; b+; c+; cout<<a<<' '<<b<<' '<<c<<endl;int main() int a=1,b=2,c=3; f1(); f1(); f1(); cout<<a<<' '<<b<<' '<<c<<endl; return 0;【例

6、3-3】/example3_3.cpp#include <iostream>using namespace std; int main()int *iptr; /聲明 int型指針 iptrint i; /聲明int型數(shù) iiptr=&i; /取 i的地址賦給 iptri=100; /int型數(shù)賦初值cout<<"Output int i="<< i<< endl; /輸出int型數(shù)的值cout<<"Output int pointer i="<<*iptr<<e

7、ndl;/輸出指針?biāo)傅刂返膬?nèi)容return 0;【例3-4】/example3_4.cpp#include <iostream>using namespace std;int main()int *a=new int; /在堆中分配int型變量所需空間，并將起始地址賦給指針a*a=76; /將76存入指針a指向的內(nèi)存空間cout<<*a<<endl; /輸出指針a指向的內(nèi)存空間的值delete a;/釋放a指向的動態(tài)存儲空間return 0;【例3-5】/example3_5.cpp#include <iostream>using namesp

8、ace std;int main()int arraysize;int *array;cout<<"please input a number of array: "cin>>arraysize;if(array=new intarraysize)=NULL) /申請一塊連續(xù)的存儲空間cout<<"Can't allocate memory, terminating."/未分配到存儲空間exit(1); /發(fā)生錯誤，退出程序for(int count=0;count<arraysize;count+)ar

9、raycount=count*2; cout<<arraycount<<" "cout<<endl;delete array; /釋放array指向的連續(xù)存儲空間return 0;【例3-6】/example3_6.cpp#include <iostream>using namespace std;struct list/結(jié)構(gòu)體int data;list *next;class Queue/隊列類public:Queue()/構(gòu)造函數(shù)ptrf=ptrb=NULL; /將兩個指針初始化為空void enqueue(int); /

10、入隊函數(shù)int dequeue(); /出隊函數(shù)private:list *ptrf; /隊首指針list *ptrb;/隊尾指針;void Queue:enqueue(int x) /入隊函數(shù)的實現(xiàn)list *newnode=new list; /動態(tài)分配內(nèi)存 newnode->data=x;newnode->next=NULL;if(ptrb=NULL) /隊空時入隊的情況，如圖3-4所示ptrf=ptrb=newnode;else /隊非空時入隊的情況，如圖3-5所示ptrb->next=newnode; ptrb=newnode;int Queue:dequeue()

11、 /出隊函數(shù)的實現(xiàn)list *tmp;int value;value=ptrf->data;tmp=ptrf;ptrf=ptrf->next; /出隊后的情況如圖3-6所示delete tmp;return value; /返回出隊的數(shù)據(jù)項int main()Queue A; /隊列對象Aint arr=2,3,4,5,7; cout<<"入隊順序："for(int i=0;i<5;i+)cout<<arri<<" "A.enqueue(arri); /將數(shù)組元素作為數(shù)據(jù)項依次入隊cout<&l

12、t;endl<<"出隊順序："for(i=0;i<5;i+)cout<<A.dequeue()<<" " /將隊列中數(shù)據(jù)項依次出隊cout<<endl; return 0;【例3-7】/student.h#include <iostream>using namespace std;class Student /學(xué)生類的聲明 int id; /私有數(shù)據(jù)成員，外部不可見char name10; float score; /為了簡化程序，只保留了一個學(xué)生成績public: /公有成員函數(shù)，外部接

13、口void input(int pid,char *pname,float s);void modify(float s);void display();/student.cpp#include "student.h"void Student:input(int pid,char *pname,float s) /成員函數(shù)的實現(xiàn)id=pid;strcpy(name,pname);score=s;void Student:modify(float s)score=s; void Student:display() cout<<" id:"<

14、;<id<<endl; /雖在類外，成員函數(shù)仍可訪問私有成員cout<<" name:"<<name<<endl;cout<<"score:"<<score<<endl;/example3_7.cpp#include "student.h"int main()Student *pstu=new Student; /動態(tài)申請內(nèi)存空間(*pstu).input(,"Wang Li",90); /通過堆對象訪問公有成員函數(shù)(*pst

15、u).display(); /通過堆對象訪問公有成員函數(shù)(*pstu).modify(85); /通過堆對象訪問公有成員函數(shù)(*pstu).display(); /通過堆對象訪問公有成員函數(shù)delete pstu;return 0;【例3-8】/example3_8.cpp#include <iostream>using namespace std; namespace myown1 /定義名字空間myown1char *user_name="myown1"/在名字空間myown1中定義指針名user_namenamespace myown2 /定義名字空間my

16、own2char *user_name="myown2"/在名字空間myown2中定義指針名user_nameint main()cout<<"Hello, " <<myown1:user_name /用名字空間限制符訪問變量user_name<<". and goodbye!"<<endl;cout <<"Hello, " <<myown2:user_name /用名字空間限制符訪問變量user_name<<". and

17、 goodbye!"<<endl;return 0;【例3-9】/example3_9.cpp#include <iostream>using namespace std;/void v; /錯誤，不能聲明void類型的變量void *vp; /正確，可以聲明void類型的指針int main()int *ip;int i=10;vp=&i; /void類型指針指向整型變量/cout<<"*vp="<<*vp<<endl;/錯誤，void型指針在使用前必須確定類型ip=(int *)vp; /類型

18、強制轉(zhuǎn)換, void類型指針賦值給int類型指針cout<<"*ip="<<*ip<<endl; return 0;【例3-10】/example3_10.cpp#include "student.h"int main()Student s1; /定義Student類的對象s1s1.input(,"Zhang Hua",95);/通過s1訪問公有成員函數(shù)s1.display(); /通過對象訪問公有成員函數(shù)Student *pstu=&s1; /定義Student類的對象指針pstu,并指向

19、對象s1pstu->input(,"Wang Li",90); /通過指針訪問公有成員函數(shù)pstu->display(); /通過指針訪問公有成員函數(shù)(*pstu).modify(85); (*pstu).display();return 0;【例3-11】/example3_11.cpp#include <iostream>using namespace std;class Boxpublic:Box(); Box(int h,int w ,int len):height(h),width(w),length(len)int volume();Bo

20、x();private:int height;int width;int length;Box:Box() height=10;width=10;length=10;Box:Box() cout<<"Destructor is called"<<endl;int Box:volume()return(height*width*length);int main()Box *pbox1=new Box; /定義指向Box堆對象的指針變量pbox1，cout<<"The volume of box1 is "<<

21、pbox1->volume()<<endl;delete pbox1; /釋放pbox1指向的對象空間Box *pbox2=new Box(15,30,25);/定義指向Box堆對象的指針變量pbox2， /在pbox2中存放堆對象的起始地址并初始化堆對象 cout<<"The volume of box2 is "<<pbox2->volume()<<endl;/指針訪問成員delete pbox2; /釋放pbox2指向的對象空間return 0; 【例3-12】/example3_12.cpp#include

22、 <iostream>using namespace std;void swap(int *x,int *y) /形參為指針int *temp; temp=*x;*x=*y;*y=temp;int main() int a=1,b=2; /定義變量cout<<"Before Swap a="<<a<<",b="<<b<<endl; swap(&a,&b); /函數(shù)調(diào)用 cout<<"After Swap a="<<a<

23、<",b="<<b<<endl; return 0;【例3-13】/example3_13.cpp#include <iostream>using namespace std;class CStrtemppublic: CStrtemp(char *s); CStrtemp(const CStrtemp&); /復(fù)制構(gòu)造函數(shù)，省略形參 CStrtemp(); /析構(gòu)函數(shù) void show(); /成員函數(shù) void set(char *s); /賦值新串函數(shù)private: char *str; /私有數(shù)據(jù)成員;CStrt

24、emp:CStrtemp(char *s)cout<<"constructor."<<endl;str=new charstrlen(s)+1; /動態(tài)申請內(nèi)存單元，見3.2.3節(jié)if(!str)cerr<<"Allocationg Error"<<endl;/cerr是標(biāo)準(zhǔn)流對象，參看第8章exit(1);/發(fā)生錯誤，退出程序strcpy(str,s); /將字符串復(fù)制到str指向的存儲空間中CStrtemp:CStrtemp(const CStrtemp& temp) /復(fù)制構(gòu)造函數(shù)的實現(xiàn) co

25、ut<<"copy constructor."<<endl; str=new charstrlen(temp.str)+1; if(!str) cerr<<"error in apply new space."<<endl; exit(1); /發(fā)生錯誤，退出程序 strcpy(str,temp.str);CStrtemp:CStrtemp() /析構(gòu)函數(shù)cout<<"destructor."<<endl;if(str!=NULL)delete str; /釋放s

26、tr指向的存儲空間void CStrtemp:show() /成員函數(shù)cout<<str<<endl;void CStrtemp:set(char *s) /成員函數(shù)的實現(xiàn) delete str; /釋放str指向的存儲空間 str=new charstrlen(s)+1; if(!str) cerr<<"Allocation Error"<<endl; exit(1); /發(fā)生錯誤，退出程序 strcpy(str,s);CStrtemp Input(CStrtemp *temp) /對象指針用做函數(shù)參數(shù) char s20;

27、cout<<"Please input the string:" cin>>s; /輸入新字符串 temp->set(s); /指針訪問成員函數(shù) return *temp; /返回指針?biāo)赶虻膶ο骾nt main() CStrtemp A("hello"); /用字符串"hello"初始化對象A A.show(); CStrtemp B=Input(&A); /用對象指針?biāo)赶虻膶ο蟪跏蓟瘜ο驜 A.show(); B.show(); return 0;【例3-14】/point.h #inclu

28、de<iostream> #include<cmath> using namespace std; class point /聲明類 public: point(double=0,double=0);/構(gòu)造函數(shù) double Getx(); /成員函數(shù)原型 double Gety(); void Setxy(double,double); point(); private: double x,y; ; const int num=10; /申請數(shù)量 void Set(point *); /普通函數(shù)原型 void Display(point *);double Lenth

29、(point *); /point.cpp#include"point.h" /定義類的成員函數(shù) point:point(double a,double b) x=a; y=b; double point:Getx() return x; double point:Gety() return y; void point:Setxy(double a,double b) x=a; y=b; point:point() cout<<"delete it:"<<x<<","<<y<<

30、;endl; /example3_14.cpp#include"point.h" int main() point *p=new point10;/申請10個對象的內(nèi)存 if(p=NULL) /如果沒有申請到,則退出程序 cout<<"地址申請失敗,結(jié)束程序運行。n" return 0; Set(p); /調(diào)數(shù)據(jù)輸入函數(shù) cout<<"內(nèi)存塊的數(shù)據(jù)如下:"<<endl; Display(p); /顯示數(shù)據(jù) cout<<"組成的折線長度為:" cout<<L

31、enth(p)<<endl; /輸出折線長度 delete p; /釋放內(nèi)存 return 0; /給內(nèi)存塊賦值的函數(shù) void Set(point *p) double a,b; for(int i=0;i<num;i+) cout<<"Input 第"<<i+1<<"個對象的兩個數(shù)據(jù)成員的值:" cin>>a>>b; (p+i)->Setxy(a,b); /給申請的內(nèi)存塊賦值 /顯示內(nèi)存塊的值的函數(shù) void Display(point *p) for(int i=0

32、;i<num;i+) cout<<(p+i)->Getx()<<","<<(p+i)->Gety()<<endl; /計算折線長度的函數(shù) double Lenth(point *p) double sum(0.0), a1,b1,a2,b2; a1=p->Getx(); /保存第一個點坐標(biāo)的x值 b1=p->Gety(); /保存第一個點坐標(biāo)的y值 for(int i=1;i<10;i+) a2=(p+i)->Getx(); /取下一點的x坐標(biāo) b2=(p+i)->Gety();

33、 /取下點的Y坐標(biāo) sum=sum+sqrt(a1-a2)*(a1-a2)+(b1-b2)*(b1-b2); /累計長度 a1=a2; /依次平移 b1=b2; /依次平移 return sum; 【例3-15】/example3_15.cpp#include <iostream>using namespace std;class Boxpublic: Box(int h=10,int w=12,int len=15):height(h),width(w),length(len) /帶默認(rèn)參數(shù)的構(gòu)造函數(shù)，含成員初始化表int volume();private: int height

34、; int width; int length;int Box:volume()return(height*width*length); int main() Box a,b(15,18,20),c(16,20,26); cout<<"volume of a is "<<a.volume()<<endl; cout<<"volume of b is "<<b.volume()<<endl; cout<<"volume of c is "<<

35、c.volume()<<endl; return 0;【例3-16】/example3_16.cpp#include <iostream>using namespace std;class Testpublic:Test(int=0);void print();private:int x;Test:Test(int a) x=a;void Test:print()cout<<"x="<<x<<"nthis->x="<<this->x <<"n(*th

36、is).x="<<(*this).x<<endl;int main() Test t(12);t.print();return 0;【例3-17】/example3_17.cpp#include <iostream>using namespace std;class Apublic:A()i=0; void add()i+;A *sp()return this; /定義指針函數(shù)sp()，顯式使用thisint Is(A *s)return s->i; /通過對象指針訪問私有數(shù)據(jù)成員private: int i; ;A *p2; /定義全局對象

37、指針數(shù)組p2int main()A a1,*a2=new A; /定義對象指針a2p0=a1.sp();p1=a2;p0->add(); /通過對象指針訪問公有成員函數(shù)a2->add();p1->add();cout<<"a1-this:"<<p0<<" a2-this:"<<p1<<endl;cout<<"i-(a1):"<<p1->Is(p0)<<" i-(a2):"<<p0-&g

38、t;Is(p1)<<endl;return 0;【例3-18】/example3_18.cpp#include <iostream>using namespace std;class Point public: Point(int xx=0,int yy=0)X=xx;Y=yy;/構(gòu)造函數(shù) int GetX()return X; int GetY()return Y;private: int X,Y;int main() Point A(4,5);/聲明對象A Point *p1=&A;/聲明對象指針并初始化 int (Point:*pGetX)()= Poin

39、t:GetX;/聲明成員函數(shù)指針并初始化 cout<<(A.*pGetX)()<< 't' /使用成員函數(shù)指針訪問成員函數(shù) cout<<(p1->GetX)()<< 't' /使用對象指針訪問成員函數(shù) cout<<A.GetX()<<endl;/使用對象名訪問成員函數(shù) return 0;【例3-19】/example3_19.cpp#include <iostream>using namespace std;class Point public: Point(int xx=

40、0,int yy=0)X=xx;Y=yy;count+;/構(gòu)造函數(shù) Point(const Point &p);/復(fù)制構(gòu)造函數(shù)的聲明 int GetX()return X; int GetY()return Y; static int count;/靜態(tài)數(shù)據(jù)成員private: int X,Y; ;int Point:count=0;/靜態(tài)數(shù)據(jù)成員的初始化Point:Point(const Point &p) /復(fù)制構(gòu)造函數(shù)的實現(xiàn) X=p.X; Y=p.Y; count+;int main()/主函數(shù) int *countp=&Point:count;/聲明一個int型

41、指針，指向類的靜態(tài)成員 Point A(4,5);/聲明對象A cout<< "Point A: "<<A.GetX()<<","<<A.GetY();/通過對象訪問成員函數(shù) cout<< " Object id= "<<*countp<<endl;/通過指針訪問靜態(tài)數(shù)據(jù)成員 Point B(A);/聲明對象B cout<< "Point B: "<<B.GetX()<<","

42、<<B.GetY(); cout<< " Object id= "<<*countp<<endl;/通過指針訪問靜態(tài)數(shù)據(jù)成員 return 0;【例3-20】/example3_20.cpp#include <iostream>using namespace std;class Point public: Point(int xx=0,int yy=0)X=xx;Y=yy;count+;/構(gòu)造函數(shù) Point(const Point &p);/復(fù)制構(gòu)造函數(shù) int GetX()return X; int G

43、etY()return Y; static void GetC()cout<<" Object id= "<<count<<endl;/靜態(tài)成員函數(shù)private: int X,Y; static int count;/靜態(tài)數(shù)據(jù)成員的初始化;Point:Point(const Point &p) X=p.X; Y=p.Y; count+;int Point:count=0; /靜態(tài)數(shù)據(jù)成員的初始化int main()/主函數(shù) void (*gc)()=Point:GetC;/聲明一個指向函數(shù)的指針，指向類的靜態(tài)成員函數(shù) Point

44、 A(4,5);/聲明對象A cout<<"Point A: "<<A.GetX()<<","<<A.GetY(); gc();/通過指針訪問靜態(tài)成員函數(shù) Point B(A);/聲明對象B cout<<"Point B: "<<B.GetX()<<","<<B.GetY(); gc();/通過指針訪問靜態(tài)成員函數(shù) return 0;【例3-21】/example3_21.cpp#include <iostream

45、>using namespace std;int main() int a=5,b=5; int *ptr = &b; /定義并初始化指針 int & ref = a; /定義并初始化引用 *ptr += 2; ref += 2; cout<<"a = "<<a<<endl; cout<<"b = "<<b<<endl;【例3-22】/example3_22.cpp#include <iostream>using namespace std;int

46、main() int *ptr,a=10,b = 20; /定義指針，但未初始化 int & ref ; /定義引用，但未初始化 int &ref1 = 100; /用常量初始化非常量引用 const int &ref2 = 100; /用常量初始化常量引用 int & ref3 = a; ref2 += 2; ref3+;ref3 = b;cout<<" a = "<<a<<endl; return 0;【例3-23】/example3_23.cpp#include <iostream>usi

47、ng namespace std;int main() int a=1; int *p = &a; int & r = a; cout<<"取變量a的地址："<<&a<<endl; /取變量a的地址 cout<<"取指針p的地址："<<&p<<endl; /取指針p的地址 cout<<"取引用r的地址："<<&r<<endl; /取引用r的地址return 0;【例3-24】/exampl

48、e3_24.cpp#include <iostream>using namespace std;void swap(int& x,int& y) /形參為引用 int temp; temp=x;x=y;y=temp;int main() int a=1,b=2; /定義變量cout<<"Before Swap a="<<a<<",b="<<b<<endl; swap(a,b); /函數(shù)調(diào)用 cout<<"After Swap a="&l

49、t;<a<<",b="<<b<<endl; return 0;【例3-25】/example3_25.cpp#include <iostream>using namespace std;class CStrtemppublic: CStrtemp(char *s); CStrtemp(const CStrtemp&); /復(fù)制構(gòu)造函數(shù)，省略形參 CStrtemp(); /析構(gòu)函數(shù) void show(); /成員函數(shù) void set(char *s); /賦值新串函數(shù)private: char *str; /私

50、有數(shù)據(jù)成員;CStrtemp:CStrtemp(char *s)cout<<"constructor."<<endl;str=new charstrlen(s)+1; /動態(tài)申請內(nèi)存單元，見3.2.3節(jié)if(!str)cerr<<"Allocationg Error"<<endl;/cerr是標(biāo)準(zhǔn)流對象，參看第8章exit(1);/發(fā)生錯誤，退出程序strcpy(str,s); /將字符串復(fù)制到str指向的存儲空間中CStrtemp:CStrtemp(const CStrtemp& temp) /復(fù)

51、制構(gòu)造函數(shù)的實現(xiàn) cout<<"copy constructor."<<endl; str=new charstrlen(temp.str)+1; if(!str) cerr<<"error in apply new space."<<endl; exit(1); /發(fā)生錯誤，退出程序 strcpy(str,temp.str);CStrtemp:CStrtemp() /析構(gòu)函數(shù)cout<<"destructor."<<endl;if(str!=NULL)delet

52、e str; /釋放str指向的存儲空間void CStrtemp:show() /成員函數(shù)cout<<str<<endl;void CStrtemp:set(char *s) /成員函數(shù)的實現(xiàn) delete str; /釋放str指向的存儲空間 str=new charstrlen(s)+1; if(!str) cerr<<"Allocation Error"<<endl; exit(1); /發(fā)生錯誤，退出程序 strcpy(str,s);CStrtemp Input(CStrtemp &temp) /對象引用做函

53、數(shù)參數(shù) char s20; cout<<"Please input the string:" cin>>s; /輸入新字符串 temp.set(s); /對象引用訪問成員函數(shù) return temp; /返回對象引用int main() CStrtemp A("hello"); /用字符串"hello"初始化對象A A.show(); CStrtemp B=Input(A); /用對象指針?biāo)赶虻膶ο蟪跏蓟瘜ο驜 A.show(); B.show(); return 0;【例3-36】/example3_36.cpp#include <iostream>#include <string>#include <cstdlib>using namespace std;class CStrtemppublic: CStrtemp(char *s) str=s;/將字符串賦給string對象 CStrtemp(const CStrtemp&); /復(fù)制構(gòu)造函數(shù)的聲明，省略形參 void show() /成員函數(shù) cout<<str<<endl; /輸出string對象 void