第8章《解析与实训》习题答案

第八章一、选择题1、D2、A3、C4、A5、B6、B7、A8、B9、C 10、C11、B 12、A 13、A 14、B 15、B 16、D 17、C 18、C 19、D 20、B21、C 22、B 23、C 24、B 25、D 26、C二、填空题1．继承2．私有派生3．（1）私有成员（2）公有派生时的公有成员或保护派生时的保护成员或私有派生时的私有成员（3）保护成员4．（1）公有成员（2）保护成员5．定义派生类时所继承的基类的顺序6．不可以7．static8．非静态9．类A210．（1）A::c B::c a1 （2）A::b A::c B::a B::b B::c a111．a2、a312．构造函数B构造函数A构造函数C析构函数~C析构函数~A析构函数~B13．0,0,0,00,1,0,00,2,3,00,5,10,1514．构造函数A构造函数C构造函数B构造函数D析构函数~D析构函数~B析构函数~C析构函数~A15．Base defaultclass Inh1class Inh2class Inh316．（1）y=200 cc （2）y=600 bb 17．(1,2)(6,9)5,6(6,9)18．n=2519．d=220．1020102021．i=2 j=3 x=4 y=5i=100 j=200 x=300 y=400i=2 j=3 x=300 y=40022．A:1i=100count=1i=300count=1A:2A:3~A:2~A:1~A:023．（1）protected （2）public （3）C(int m,int n,int k):A(m),b1(n) （4）cout<<a<<‘\t’<<b1.b<<‘\t’<<c<<‘\n’;24．（1）A(x), B(y) （2）c1.A::geta( ) （3）c1.B::geta( ) （4）c1.geta( )25．（1）friend float Print(tria Tria); （2）a=x;b=y;c=z; （3）tria Tria (4) Print(a)26．（1）class A （2）public: （3）friend void B::disp1(A tmp) （4）friend void B::disp2(A tmp)27．（1）static int y （2）int A::y （3）A::y三、改错题1．# include <iostream.h>class A{int a;A( ) { a=5; }friend class B;friend void main( );};class B{A a1;public :friend C; //改为friend class C;int geta( ){ return a1.a; }};class C{public :A a2;};void main( ){ A a1;cout<<a1.a<<'\t';B b1;cout<<b1.geta( )<<'\t';C c1;/*由类C生成对象c1时隐含通过类缺省构造函数调用了类A的//构造函数来生成成员对象a2，但类A的函数是私有的。

*/cout<<c1.a2.a<<'\n';}2.#include <iostream.h>class A{int i; //改为static int i;public :static int j;A(int a , int b){ i=a; j=b; }static void get( ){ cout<<"i="<<i<<'\n';cout<<"j="<<j<<'\n';}};int A::j=0;// 增加说明语句int A::i=0;void main( ){ A a1(4 , 8);A::get( );}3.#include <iostream.h>class A{ //增加protected:int a;public :A(int x){ a=x; }};class B : public A{int a;public :B(int x=0) //改为B(int x=0):A(x) { a=x; }void show( ){ cout<<a<<‘\t’<<A::a<<‘\n’; } };void main( ){ B b1;b1.show( );}四、编程题1．#include<iostream.h>#include<string.h>#define N 2class Person{protected:int no;char name[8],sex;public:void input(){cout<<"编号：";cin>>no;cout<<"姓名：";cin>>name;cout<<"性别：";cin>>sex;}void show(){cout<<"编号："<<no<<endl;cout<<"姓名："<<name<<endl;cout<<"性别："<<sex<<endl;}};class Birthday{protected:int year;int month;int day;public:void input(){ cout<<"出生日期："<<endl;cout<<"年：";cin>>year;cout<<"月：";cin>>month;cout<<"日：";cin>>day;}void show(){cout<<"出生日期："<<year<<"年"<<month<<"月"<<day<<"日"<<endl;}};class Student:public Person,public Birthday{float Cpp;public:void input(){Person::input();Birthday::input();cout<<"Cpp成绩：";cin>>Cpp;}void show(){Person::show();Birthday::show();cout<<"Cpp成绩："<<Cpp<<endl;}};class Teacher:public Person,public Birthday{char prof[10];char depart[10];public:void input(){Person::input();Birthday::input();cout<<"职称：";cin>>prof;cout<<"部门：";cin>>depart;}void show(){Person::show();Birthday::show();cout<<"职称："<<prof<<endl;cout<<"部门："<<depart<<endl;}};void main(){ Student s1;Teacher t1;cout<<"输入1个学生的数据：\n";s1.input();cout<<"输入1个教师的数据：\n";t1.input();cout<<"输出1个学生的数据：\n";s1.show();cout<<"输出1个教师的数据：\n";t1.show();}2.#include<iostream.h>#include<string.h>class G{ //基类车protected:char num[10]; //车牌号int year,month,day;public:G(char *nu,int y,int m,int d){strcpy(num,nu);year=y;month=m;day=d;}};class C:public G{ //轿车protected:int pn; //人数public:C(char *nu,int y,int m,int d,int p):G(nu,y,m,d){ pn=p; }void setdata(char *nu,int y,int m,int d,int p){strcpy(num,nu);year=y;month=m;day=d;pn=p;}void Print( ){ cout<<num<<"\t"<<year<<"\t"<< month<<"\t"<<day<<"\t"<<pn<<endl; } };class A:public C{ //客车int ln; //车轮数public:A(char *nu,int y,int m,int d,int p,int l):C(nu,y,m,d,p){ ln=l; }void setdata(char *nu,int y,int m,int d,int p,int l){strcpy(num,nu);year=y;month=m;day=d;pn=p;ln=l;}void Print() {cout<<num<<"\t"<<year<<"\t"<<month<<"\t"<<day<<"\t"<<pn<<"\t"<<ln<<endl;}};class B:public G{ //货车float tn; //重量int ln; //车轮数public:B(char *nu,int y,int m,int d,float t,int l):G(nu,y,m,d){tn=t;ln=l;}void setdata(char *nu,int y,int m,int d,float t,int l) {strcpy(num,nu);year=y;month=m;day=d;tn=t;ln=l;}void Print( ){cout<<num<<"\t"<<year<<"\t"<<month<<"\t"<<day<<"\t" <<tn <<"\t"<<ln<<endl;}};void main( ){C cc("苏L0001",1995,5,15,6);A aa("苏L1001",1995,5,15,36,8);B bb("苏L2001",1995,5,15,4.5,6);cc.Print();aa.Print();bb.Print();cout<<endl;aa.setdata("苏L1007",2003,5,25,100,16);bb.setdata("苏L2008",2002,2,2,12,24);cc.setdata("苏L0005",2003,5,20,11);cc.Print();aa.Print();bb.Print();}3．#include <iostream.h>class A{float balance;public:A(float x=0){ balance=x; }friend float total(A a){ return a.balance; } };class B{float balance;public:B(float x=0){ balance=x; }friend float total(B b){ return b.balance; } };class C{float balance;public:C(float x=0){ balance=x; }friend float total(C c){ return c.balance; } };void main( ){ A a(2e5);B b(3.5e5);C c(2.8e4);cout<<"total="<<total(a)+total(b)+total(c)<<'\n';}或#include <iostream.h>class A{float balance;public:A(float x=0){ balance=x; }friend void total(A a,float *s){ *s+=a.balance; } };class B{float balance;public:B(float x=0){ balance=x; }friend void total(B b,float *s){ *s+=b.balance; } };class C{float balance;C(float x=0){ balance=x; }friend void total(C c,float *s){ *s+=c.balance; } };void main( ){ float sum=0;A a(2e5);B b(3.5e5);C c(2.8e4);total(a,&sum);total(b,&sum);total(c,&sum);cout<<"total="<<sum<<'\n';}4．#include <iostream.h>#include<string.h>class score{char *name,*id;float mat,eng,phy;static float sumfs;score(){ cout<<"请输入学生信息!\n";cout<<"姓名学号数学英语物理\n";char n[15];cin>>n;name=new char[strlen(n)+1];strcpy(name,n);char i[10];cin>>i;id=new char[strlen(i)+1];strcpy(id,i);float x,y,z;cin>>x>>y>>z;mat=x;eng=y;phy=z;sumfs=mat+eng+phy;}static float rsumfs(){ return sumfs; }~score(){ delete []name; delete []id; } };float score::sumfs;void main( ){ int n;cout<<"请输入班级人数: ";cin>>n;for(int i=0;i<n;i++){score sc;cout<<"sum="<<sc.rsumfs()<<'\n';}}五、实验1.#include<iostream.h>#include<string.h>class Employee{ //基类protected:char name[16];double salary;int no;public:Employee( ){cout<<"员工编号：";cin>>no;cout<<"员工姓名：";cin>>name;salary=0;}void pay();void display();};class Manager:virtual public Employee{protected:double monthpay;public:Manager(){ monthpay=8000; }void pay(){ salary=monthpay;}void display(){cout<<"经理"<<name<<"编号:"<<no<<"本月工资："<<salary<<endl; }};class Salesman:public virtual Employee{protected:double commrate;double sales;public:Salesman(){commrate=0.04;}void pay(){cout<<name<<"本月销售额：";cin>>sales;salary=sales*commrate;}void display(){cout<<"销售员"<<name<<"编号:"<<no<<"本月工资："<<salary<<endl; }};class Manager_Salesman:public Manager,public Salesman{public:Manager_Salesman(){monthpay=5000;commrate=0.005;}void pay(){cout<<name<<"所管部门月销售额：";cin>>sales;salary=monthpay+sales*commrate;}void display(){cout<<"销售经理"<<name<<"编号:"<<no<<"本月工资："<<salary<<endl; }};void main(){ Manager m1;Salesman s1;Manager_Salesman ms1;m1.pay();m1.display();s1.pay();s1.display();ms1.pay();ms1.display();}2．#include <iostream.h>#define PAI 3.1415927class A{float r,h;public:A(float x,float y){r=x;h=y;}float Getr( ){ return r; }float Geth(){ return h; }friend double V1(A a){ return PAI*a.r*a.r*a.h; }} ;double V2(double r,double h){ return PAI*r*r*h; }void main( ){A a(10,5);cout<<"r="<<a.Getr()<<"\th="<<a.Geth()<<'\n';cout<<"Volum="<<V1(a)<<'\n';cout<<"Volum="<<V2(a.Getr(),a.Geth())<<'\n';}。