继承与多态性习题参考答案.docx

1、继承与多态性习题参考答案继承与多态性习题参考答案 作者： 日期： C+程序设计语言习题及实验指导第8章 继承与多态性习题参考答案8.3 习题8.3.1 选择题题号12345678910答案CDADABCBDD题号11121314151617181920答案DDACBCCCAC8.3.2 填空题1 (1) a、b、c、x、y、z (2) b、y (3) c、z (4) a、x (5) b、c、x、y、z (6) b、y (7) y (8) b、c、z (9) a、x (10) b、c、x、y、z (11) y (12) y (13) z (14) a、b、c、x (15) b、c、x、y、z (

2、16) y2 私有3 抽象4 虚基5 (1) 基类 (2) 对象6 (1) 静态 (2) 编译 (3) 虚函数7 (1) 2 1 (2) 0 58 (1) 100 200 300 30 (2) 10 100 (3) 20 2009 (1) 5 10 (2) end. (3) 20 1010(1) classA classB (2) end. (3) classB classA11(1) 10 (2) build B (3) build C (4) release A12(1) class B (2) class C (3) class D (4) 513(1) 5 5 (2) 20 2014(

3、1) 10 (2) 10 2015(1) 1 (2) 3 (3) 5 (4) 100 1016(1) B:f() (2) B:fun() (3) A:f() (4) B:fun()17(1) 姓名陈涛年薪6.8万元。 (2) 姓名李原 (3) 姓名李原月工资4000元18(1) 110 (2) 222019(1) protected 或public (2) Base1(s1),Base2(s2) 或Base2(s2),Base1(s1) (3) Base1:str (4) test.print()20(1) virtual void show()=0 (2) C(int,int,int) （注

4、：参数可有任一名称） (3) b1(y) (4) &t8.3.3 编程题1求长方形的面积和长方体的表面积、体积#includeclass Rectangleprotected: float L; / 长方形的长 float W; / 长方形的宽 float area; / 长方形的面积public: Rectangle(float L1,float W1) L=L1; W=W1; void function() area=L*W; void show() cout长为L，宽为W的长方形面积为areaendl; ; class Cuboid:public Rectangle float H; /

5、 长方体的高 float volume; / 长方体的体积public: Cuboid(float a,float b,float c):Rectangle(a,b) H=c; void function() area=(L*W+L*H+W*H)*2; void fun() volume=L*W*H; void show() cout长为L，宽为W，高为H的长方体表面积为area，体积为volumeendl; ; void main() Rectangle r(2,3); r.function(); r.show(); Cuboid c(2,3,4); c.function(); c.fun(

6、); c.show();2产生并输出圆桌信息#include#includeclass Circleprotected: double radius; double area;public: Circle(double r) radius=r; ; class Tableprotected: double height;public: Table(double h) height=h; ; class Roundtable:public Table,public Circle char *color;public: Roundtable(double h,double r,char c):Ci

7、rcle(r),Table(h) color=new charstrlen(c)+1; strcpy (color, c); void fun() area=3.14*radius*radius; void show() cout高度：height米endl; cout面积：area平方米endl; cout颜色：colorendl; Roundtable() delete color; ;void main() Roundtable rt(0.75,1.1,黑色); rt.fun(); rt.show();3计算企业的经营税#include#includeclass Taxprotected

8、: char name50; / 企业名称 double income; / 经营收入 double taxes; / 税金public: Tax(char *n,double in) strcpy(name,n); income=in; virtual void fun()=0; void show() coutname的经营收入为income万元，税金为taxes万元n; ; class Service:public Taxpublic: Service(char *n,double in):Tax(n,in) void fun() taxes=income*5/100; ; class

9、Fabrication:public Taxpublic: Fabrication(char *n,double in):Tax(n,in) void fun() taxes=income*17/100; ;void print(Tax &t) t.fun(); t.show(); void main() char name50; int income; coutname; coutincome; Service s(name,income); print(s); coutname; coutincome; Fabrication f(name,income); print(f);4把原始体育

10、成绩转换为等第#includeclass Sportsprotected: int item; / 项目 char name20; / 姓名 double score; / 原始成绩 char grade10; / 评定等第public: Sports(int i,char *n) item=i; strcpy(name,n); coutscore; void show() coutname的item米成绩为score秒,等第为gradeendl; virtual void change()=0; class Run50:public Sportspublic: Run50(int i,cha

11、r *n):Sports(i,n) void change() if(score=6.50)strcpy(grade,优秀); else if(score=6.70)strcpy(grade,良好); else if(score=7.10)strcpy(grade,及格); else strcpy(grade,不及格); ; class Run100:public Sportspublic: Run100(int i,char *n):Sports(i,n) void change() if(score=13.10)strcpy(grade,优秀); else if(score=13.70)s

12、trcpy(grade,良好); else if(score=14.90)strcpy(grade,及格); else strcpy(grade,不及格); ; class Run1000:public Sportspublic: Run1000(int i,char *n):Sports(i,n) void change() if(score=203.00)strcpy(grade,优秀); else if(score=213.00)strcpy(grade,良好); else if(score=233.00)strcpy(grade,及格); else strcpy(grade,不及格);

13、 ; class Run1500:public Sportspublic: Run1500(int i,char *n):Sports(i,n) void change() if(score=323.00)strcpy(grade,优秀); else if(score=337.00)strcpy(grade,良好); else if(score=365.00)strcpy(grade,及格); else strcpy(grade,不及格); ; void main() Sports *s; int it; coutit; char na20; coutna; if(it=50) Run50 r

14、50(it,na); s=&r50; s-change(); s-show(); else if(it=100) Run100 r100(it,na); s=&r100; s-change(); s-show(); else if(it=1000) Run1000 r1000(it,na); s=&r1000; s-change(); s-show(); else if(it=1500) Run1500 r1500(it,na); s=&r1500; s-change(); s-show(); else cout输入项目错误n; exit(0); 8.4 实验指导8.4.1 派生类的定义与使用

15、：设计一个程序求三角函数的值。#include#includeclass Trigonometricprotected: double arc; double value;public: Trigonometric(int t) arc=t%360*3.14159/180; value=0; ;class Sine:public Trigonometricpublic: Sine(int t):Trigonometric(t) double f1(double x,int n) double t=1; for(int i=0;i=1e-6); void show() coutsin(arc)=

16、valueendl; ;void main() int d; coutd; Sine sin(d); sin.function(); sin.show();8.4.2 虚函数实现运行多态性：设计一个程序判断某人是否为优秀教师或优秀学生。#includeclass Peopleprotected: char category20; / 人员类别 char name10; / 姓名 int num; / 分数或论文数 int result; / 结论，1为优秀，0为不优秀public: People( ) coutcategory; coutname; void show() if(result)

17、coutname是优秀categoryendl; else coutname不是优秀categoryendl; virtual void inputnum()=0; virtual void isgood( )=0; ; class Student:public Peoplepublic: void inputnum() coutnum; void isgood( ) result=(num90)? 1 : 0; ; class Teacher:public Peoplepublic: void inputnum( ) coutnum; void isgood( ) result=(num5)? 1 : 0 ; ; void main() People *p; Student s; p=&s; p-inputnum(); p-isgood(); p-show(); / A Teacher t; p=&t; p-inputnum(); p-isgood(); p-show(); / B