內(nèi)蒙古科技大學(xué)面向?qū)ο蟮某绦蛟O(shè)計(jì)實(shí)驗(yàn)6-靜態(tài)成員和友元(共19頁)

1、精選優(yōu)質(zhì)文檔-傾情為你奉上內(nèi)蒙古科技大學(xué)面向?qū)ο蟮某绦蛟O(shè)計(jì)實(shí)驗(yàn)報(bào)告  課程名稱：面向?qū)ο蟮某绦蛟O(shè)計(jì)姓名：陳偉光實(shí)驗(yàn)名稱：靜態(tài)成員和友元學(xué)號：任課教師：劉月峰專業(yè)：軟件工程指導(dǎo)教師：劉月峰班級：15-軟件一班  一、實(shí)驗(yàn)?zāi)康?#160; 1理解靜態(tài)成員（靜態(tài)數(shù)據(jù)成員、靜態(tài)成員函數(shù)）的作用與使用；2理解友元（友元函數(shù)、友元類）的作用于使用。二、實(shí)驗(yàn)環(huán)境編譯器：Visual C+ 6.0.操作系統(tǒng)：Windows 7 旗艦版 三、實(shí)驗(yàn)內(nèi)容 二、實(shí)驗(yàn)內(nèi)容2.1練習(xí)（一）：1理解下面的程序，并在VC+6.0下運(yùn)行查看結(jié)果，回

2、答程序后面的問題。#include <iostream.h>#include <string.h>class CStudentpublic:CStudent(char *n, int a);CStudent();static void SetAge(int age);private:char *name;int age;static int nTotalObj;int CStudent:nTotalObj = 0;CStudent:CStudent(char *n, int a):age(a)int nLen = strlen(n);name = new charnLe

3、n+1;strcpy(name,n);namenLen = 0;nTotalObj+;CStudent:CStudent()delete name;nTotalObj-;void CStudent:SetAge(int age)this->age = age;void main()CStudent stu1("張三",25);CStudent str2("李四",26);cout<<"CStudent:nTotalObj="<<CStudent:nTotalObj<<endl;問題一：以上程序

4、編譯能通過嗎，為什么？問題二：成員變量nTotalObj在程序中起什么作用，它是如何實(shí)現(xiàn)的？問題三：如果規(guī)定該程序的主函數(shù)和類CStudent中的成員變量的屬性不允許改變，應(yīng)該如何改正該程序？2理解下面的程序，并在VC+6.0下運(yùn)行查看結(jié)果，回答程序后面的問題。#include <iostream.h>#include <string.h>class CStudentpublic:CStudent(char *n, int a);CStudent();private:char *name;int age;CStudent:CStudent(char *n, int a)

5、:age(a)int nLen = strlen(n);name = new charnLen+1;strcpy(name,n);namenLen = 0;CStudent:CStudent()delete name;class CTeacherpublic:CTeacher(char *tn, int ta);CTeacher();void SetStuAge(int a); private:char *name;int age;CStudent stu;CTeacher:CTeacher(char *tn, int ta):age(ta)int nLen = strlen(tn)

6、;name = new charnLen+1;strcpy(name,tn);namenLen = 0;CTeacher:CTeacher()delete name;void CTeacher:SetStuAge(int a)stu.age = a;void main()CStudent stu("張三",25);CTeacher tea("李四",26);問題一：以上程序有兩大錯(cuò)誤，試指出來，并改正之？2.2練習(xí)（二）：1某商店經(jīng)銷一種貨物。貨物成箱購進(jìn)，成箱賣出，購進(jìn)和賣出時(shí)以重量為單位，各箱的重量不一樣，因此，商店需要記錄下貨物庫存的總重量。試用C

7、+模擬商店貨物購進(jìn)和賣出的情況。（提示：將總重量定義為靜態(tài)成員）四、實(shí)驗(yàn)過程練習(xí)1 題目提供源代碼如下編譯結(jié)果如下分析之后得出結(jié)論首先靜態(tài)成員函數(shù)SetAge中不可以使用指針，也不可以直接使用非靜態(tài)數(shù)據(jù)成員age 此處應(yīng)該使用對象名或者類名間接引用age 其次nTotalObj為私有屬性，不可以直接訪問，且題目要求不可以修改其屬性，則添加一個(gè)成員函數(shù)，使其返回值等于nTotalObj,則代替了原先nTotalObj的功能 修改之后的代碼如下然后再次編譯運(yùn)行結(jié)果如下運(yùn)行結(jié)果正確，且不影響nTotalObj的計(jì)數(shù)器功能，代碼修改正確 練習(xí)2題目提供源代碼如下編譯之后結(jié)

8、果如下分析錯(cuò)誤原因有兩點(diǎn)錯(cuò)誤1 CTeacher類中的成員函數(shù)SetStuAge不能直接訪問CStudent類內(nèi)嵌成員stu的數(shù)據(jù)成員age錯(cuò)誤2 CTeacher類構(gòu)造函數(shù)的初始化含有錯(cuò)誤,內(nèi)嵌對象stu的數(shù)據(jù)成員也應(yīng)該包含在內(nèi) 修改之后代碼如下運(yùn)行結(jié)果如下成功運(yùn)行，修改正確 練習(xí)3根據(jù)題意，所編寫代碼如下嘗試測試運(yùn)行結(jié)果該代碼包含題目要求的所有功能，運(yùn)行完畢 五、實(shí)驗(yàn)總結(jié)實(shí)驗(yàn)源代碼:練習(xí)（一）  /修改之后代碼#include <iostream.h>#include <string.h>class CStudent

9、public:      CStudent(char *n, int a);      CStudent();      static void SetAge(CStudent stuN);      static int CSnTota10bj();         

10、           private:      char *name;      int age;      static int nTotalObj;int CStudent:nTotalObj = 0;CStudent:CStudent(char *n, int a):age(a)  

11、;    int nLen = strlen(n);      name = new charnLen+1;      strcpy(name,n);      namenLen = 0;      nTotalObj+;        &

12、#160;                           CStudent:CStudent()      delete name;      nTotalObj-; int CStudent:

13、CSnTota10bj()      int n;      n=nTotalObj;      return n; void CStudent:SetAge(CStudent stuN)      int a;      stuN.age = a;void main() 

14、60;    CStudent stu1("張三",25);      CStudent str2("李四",26);      cout<<"CStudent:nTotalObj="<<CStudent:CSnTota10bj()<<endl;練習(xí)（二） #include <iostream.h>#include &l

15、t;string.h>class CStudentpublic:      CStudent(char *n, int a);      CStudent();private:      char *name;public:      int age;CStudent:CStudent(char *n, int a):age(a)  

16、;    int nLen = strlen(n);      name = new charnLen+1;                             strcpy(name,n); &

17、#160;    namenLen = 0;CStudent:CStudent()      delete name;class CTeacherpublic:      CTeacher(char *tn,int ta,char *sn,int sa);      CTeacher();      void SetS

18、tuAge(int a);private:      char *name;      int age;      CStudent stu;                       &

19、#160;                  CTeacher:CTeacher(char *tn,int ta,char *sn="noname",int sa=0):age(ta),stu(sn,sa)      int nLen = strlen(tn);      nam

20、e = new charnLen+1;      strcpy(name,tn);      namenLen = 0;CTeacher:CTeacher()      delete name;void CTeacher:SetStuAge(int a)      stu.age = a;void main()    

21、  CStudent stu("張三",25);      CTeacher tea("李四",26);  /*錯(cuò)誤1 CTeacher類中的成員函數(shù)SetStuAge不能直接訪問CStudent類內(nèi)嵌成員stu的數(shù)據(jù)成員age錯(cuò)誤2 CTeacher類構(gòu)造函數(shù)的初始化含有錯(cuò)誤,內(nèi)嵌對象stu的數(shù)據(jù)成員也應(yīng)該包含在內(nèi)*/ 練習(xí)（三）  #include <iostream.h>class Goodsprivate:

22、    int weight;    static int totalWeight;public:    Goods(int wei);    static void PrintTotalWeight();    void sell();       void buy();int Goods:totalWeight = 0;Go

23、ods:Goods(int twei)    totalWeight = twei;       cout<<"初始總重量為:"<<totalWeight<<endl; void Goods:PrintTotalWeight()    cout<<"總重量為:"<<Goods:totalWeight<<endl;void Go

24、ods:buy()       cout<<"購入"<<endl;       cout<<"請輸入購入貨物的重量:"       cin>>weight;    Goods:totalWeight += weight;   

25、60;                     weight  = 0;void Goods:sell()       cout<<"售出"<<endl;       cout<&

26、lt;"請輸入售出貨物的重量:"       cin>>weight;    Goods:totalWeight -= weight;                           

27、                    weight  = 0;void main()       int twei=0;       int swit=1;       

28、;cout<<"請?jiān)O(shè)置初設(shè)總重量"<<endl;       cin>>twei;    Goods goods1(twei);       while(swit)                

29、0;                 cout<<"請選擇操作類型:0.退出  1.購入  2.售出"<<endl;              cin>>swit;  

30、60;            switch(swit)                                  case 0:co

31、ut<<endl;                     break;              case 1:goods1.buy();                            goods1.PrintTotalWeight();