通城网站建设,uml电子商务网站建设文档,招商网站建设网,wordpress $post1.对Tv 和 Remote 类做如下修改: a#xff0c;让它们互为友元; b.在 Remote类中添加一个状态变量成员#xff0c;该成员描述遥控器是处于常规模式还是互动模式: c#xff0c;在 Remote 中添加一个显示模式的方法 d.在T类中添加一个对 Remote 中新成员进行切换的方法#xf…1.对Tv 和 Remote 类做如下修改: a让它们互为友元; b.在 Remote类中添加一个状态变量成员该成员描述遥控器是处于常规模式还是互动模式: c在 Remote 中添加一个显示模式的方法 d.在T类中添加一个对 Remote 中新成员进行切换的方法该方法应仅当 TV 处于打开状态时才能运行。 编写一个小程序来测试这些新特性。
#include iostream
#include tv.hint main()
{using std::cout;Tv s42;cout Initial settings for 42\ TV:\n;s42.settings();s42.onoff();s42.chanup();cout \nAdjusted settings for 42\ TV:\n;s42.settings();Remote grey;grey.set_chan(s42, 10);grey.volup(s42);grey.volup(s42);s42.set_status(grey);cout \n42\ settings after using remote:\n;s42.settings();grey.show_status();Tv s58(Tv::On);s58.set_mode();grey.set_chan(s58, 28);s58.set_status(grey);cout \n58\ settings:\n;s58.settings();grey.show_status();return 0;
}#ifndef TV_H_
#define TV_H_
#include iostreamclass Remote; //先声明Remote类然后再定义, 以便编译器有足够的信息编译使用Remote类的方法;class Tv
{
public:friend class Remote;enum { Off, On };enum { MinVal, MaxVal 20 };enum { Antenna, Cable };enum { TV, DVD };Tv(int s Off, int mc 125) : state(s), volume(5),maxchannel(mc), channel(2), mode(Cable), input(TV) {}void onoff() { state (state On) ? Off : On; }bool ison() const { return state On; }bool volup();bool voldown();void chanup();void chandown();void set_mode() { mode (mode Antenna) ? Cable : Antenna; }void set_input() { input (input TV) ? DVD : TV; }void settings() const;void set_status(Remote r); //对Remote类中状态成员进行切换的方法;private:int state;int volume;int maxchannel;int channel;int mode;int input;
};class Remote
{
private:int mode;int status; //状态变量成员;public:friend class Tv;enum { Convention, Interaction }; //Convention表示常规模式, Interaction表示互动模式;Remote(int m Tv::TV, int s Convention) : mode(m), status(s) {} //默认为常规模式;bool volup(Tv t) { return t.volup(); }bool voldown(Tv t) { return t.voldown(); }void onoff(Tv t) { t.onoff(); }void chanup(Tv t) { t.chanup(); }void chandown(Tv t) { t.chandown(); }void set_chan(Tv t, int c) { t.channel c; }void set_mode(Tv t) { t.set_mode(); }void set_input(Tv t) { t.set_input(); }void show_status() const;
};inline void Tv::set_status(Remote r)
{if (ison()){r.status Remote::Convention r.status ? Remote::Interaction : Remote::Convention;}
}inline void Remote::show_status() const
{std::cout Status (status Convention ? Convention : Interaction) std::endl;
}#endif#include iostream
#include tv.hbool Tv::volup()
{if (volume MaxVal){volume;return true;}return false;
}bool Tv::voldown()
{if (volume MinVal){volume--;return true;}return false;
}void Tv::chanup()
{channel channel maxchannel ? 1 channel : 1;
}void Tv::chandown()
{channel channel 1 ? channel - 1 : maxchannel;
}void Tv::settings() const
{using std::cout;using std::endl;cout TV is (state Off ? Off : On) endl;if (state On){cout Volume setting volume endl;cout Channel setting channel endl;cout Mode ;cout (mode Antenna ? antenna : cable) endl;cout Input ;cout (input TV ? TV : DVD) endl;}
}2.修改程序清单 15.11使两种异常类型都是从头文件stdexcepi提供的 logic_error 类派生出来的类让每个 what()方法都报告函数名和问题的性质。异常对象不用存储错误的参数值而只需支持 what()方法
#include iostream
#include cmath
#include exc_mean.hdouble hmean(double a, double b);
double gmean(double a, double b);int main()
{using std::cin;using std::cout;using std::endl;double x, y, z;cout Enter two numbers: ;while (cin x y){try{z hmean(x, y);cout Harmonic mean of x and y;cout is z endl;z gmean(x, y);cout Geometric mean of x and y;cout is z endl;cout Enter next set of numbers q to quit: ;}catch (bad_hmean bg){cout bg.what(); //调用what方法打印hmean中的异常;cout Try again.\n;continue;}catch (bad_gmean hg){cout hg.what(); //调用what方法打印gmean中的异常;cout Sorry, you dont get to play any more.\n;break;}}cout Bye!\n;return 0;
}double hmean(double a, double b)
{if (a -b){throw bad_hmean();}return 2.0 * a * b / (a b);
}double gmean(double a, double b)
{if (a 0 || b 0){throw bad_gmean();}return std::sqrt(a * b);
}#ifndef EXC_MEAN_H_
#define EXC_MEAN_H_
#include iostream
#include string
#include stdexcept
using namespace std;class bad_hmean : public logic_error
{
public:explicit bad_hmean(const string s Error in bad_hmean object\nhmean() arguments should be a ! -b\n) : logic_error(s) {}
};class bad_gmean : public logic_error
{
public:explicit bad_gmean(const string s Error in bad_hmean object\ngmean() arguments should be 0\n) : logic_error(s) {}
};#endif
3.这个练习与编程练习2相同但异常类是从一个这样的基类派生而来的:它是从 logic_crror 派生而来的并存储两个参数值。异常类应该有一个这样的方法:报告这些值以及函数名。程序使用一个 catch块来捕获基类异常其中任何一种从该基类异常派生而来的异常都将导致循环结束。
#include iostream
#include cmath
#include exc_mean.hdouble hmean(double a, double b);
double gmean(double a, double b);int main()
{using std::cin;using std::cout;using std::endl;double x, y, z;cout Enter two numbers: ;while (cin x y){try{z hmean(x, y);cout Harmonic mean of x and y;cout is z endl;z gmean(x, y);cout Geometric mean of x and y;cout is z endl;cout Enter next set of numbers q to quit: ;}catch (mean m) //捕获基类以及派生类的任何异常;{cout Sorry, you dont get to play any more.\n;break;}}cout Bye!\n;return 0;
}double hmean(double a, double b)
{if (a -b){bad_hmean temp(hmean, a, b);temp.mesg();throw temp;}return 2.0 * a * b / (a b);
}double gmean(double a, double b)
{if (a 0 || b 0){bad_gmean temp(gmean, a, b);temp.mesg();throw temp;}return std::sqrt(a * b);
}#ifndef EXC_MEAN_H_
#define EXC_MEAN_H_
#include iostream
#include string
#include stdexcept
using namespace std;class mean : public logic_error
{
private:double v1;double v2;public:mean(const string s none, double a 0.0, double b 0.0) : logic_error(s), v1(a), v2(b) {}const double val1() const { return v1; }const double val2() const { return v2; }
};class bad_hmean : public mean
{
public:bad_hmean(const string s none, double a 0.0, double b 0.0) : mean(s, a, b) {}void mesg() const;
};inline void bad_hmean::mesg() const
{cout hmean( val1() , val2() ): endl;cout hmean() arguments should be a ! b endl;
}class bad_gmean : public mean
{
public:bad_gmean(const string s none, double a 0.0, double b 0.0) : mean(s, a, b) {}void mesg() const;
};inline void bad_gmean::mesg() const
{cout gmean( val1() , val2() ): endl;cout gmean() arguments should be 0 endl;
}#endif4.程序清单 15.16 在每个 ty 后面都使用两个 catch 块以确保 nbad index 异常导致方法 abel_val()被调用。请修改该程序在每个 ty 块后面只使用一个 catch 块并使用 RTTI 来确保合适时调用 abel_val()
#include iostream
#include sales.hint main()
{using std::cin;using std::cout;using std::endl;double vals1[12] {1220, 1100, 1122, 2212, 1232, 2334,2884, 2393, 3302, 2922, 3002, 3544};double vals2[12] {12, 11, 22, 21, 32, 34,28, 29, 33, 29, 32, 35};Sales sales1(2011, vals1, 12);LabeledSales sales2(Blogstar, 2012, vals2, 12);cout First try block:\n;try{int i;cout Year sales1.Year() endl;for (i 0; i 12; i){cout sales1[i] ;if (i % 6 5){cout endl;}}cout Year sales2.Year() endl;cout Label sales2.Label() endl;for (i 0; i 12; i){cout sales2[i] ;if (i % 6 5){cout endl;}}cout End of try block 1.\n;}catch (Sales::bad_index bad){cout bad.what();LabeledSales::nbad_index *ni;if (ni dynamic_castLabeledSales::nbad_index *(bad)) //RTTI识别类型;{cout Company: ni-label_val() endl;cout bad index: ni-bi_val() endl;}else{cout bad index: bad.bi_val() endl;}}cout \nNext try block:\n;try{sales2[2] 37.5;sales1[20] 23345;cout End of try block 2.\n;}catch (Sales::bad_index bad){cout bad.what();LabeledSales::nbad_index *ni;if (ni dynamic_castLabeledSales::nbad_index *(bad)) //RTTI识别类型;{cout Company: ni-label_val() endl;cout bad index: ni-bi_val() endl;}else{cout bad index: bad.bi_val() endl;}}cout done\n;return 0;
}
