C++ primer plus第六版第15章编程练习

1.tv.h:

#pragma once
#include 
using namespace std;
class Tv
{
public:
  friend class Remote;
  enum { Off,On };
  enum{MinVal,MaxVal = 20};
  enum{Antenna,Cable};
  enum{TV,VCR};
  Tv(int s = Off,int mc = 100):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) ? VCR : TV; }
  void settings() const;
  void set_remote_mode(Remote& r);
private:
  int state;
  int volume;
  int maxchannel;
  int channel;
  int mode;
  int input;
};

class Remote
{
public:
  friend class Tv;
  enum{USUAL,EXCHANGE};
  Remote(int m = Tv::TV,int rm = USUAL):mode(m),remote_mode(rm){}
  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 showMode() { cout<< "Remote mode is "<

tv.cpp:

#include "Tv.h"

bool Tv::volup() {
  if (volume < MaxVal) {
    volume++;
    return true;
  }
  else
    return false;
}
bool Tv::voldown() {
  if (volume > MinVal) {
    volume--;
    return true;
  }
  else
    return false;
}
void Tv::chanup() {
  if (channel < maxchannel)
    channel++;
  else
    channel = 1;
}
void Tv::chandown() {
  if (channel > 1)
    channel--;
  else
    channel = maxchannel;
}
void Tv::settings() const {
  cout << "TV is " << (state == Off ? "Off" : "On") << endl;
  if (state == On) {
    cout << "Volume setting = " << volume << endl;
    cout << "Channel setting = " << channel << endl;
    cout << "Mode = " << (mode == Antenna ? "antenna":"cable") << endl;
    cout << "Input = " << (input == TV ? "TV" : "VCR") << endl;
  }
}

void Tv::set_remote_mode(Remote& r) {
  if (ison()) {
    r.remote_mode = Remote::EXCHANGE;
    r.showMode();
  }
}

main:

#include
#include "Tv.h"
using namespace std;
int main()
{
  Tv tv;
  Remote rm;
  rm.showMode();
  cout << "Initial settings for TV:\n";
  tv.settings();
  tv.onoff();
  tv.chanup();
  cout << "Adjusted settings for TV:\n";
  tv.settings();

  tv.set_remote_mode(rm);
  rm.set_chan(tv, 12);
  rm.volup(tv);
  rm.volup(tv);
  cout << "settings after using remote:\n";
  tv.settings();
  return 0;
}

2. exc_mean.h:

#pragma once
#include 
#include 
using namespace std;

class bad_hmean : public logic_error
{
public:
  explicit bad_hmean(const string& n = "hmean",const string& s="Error in hmean()\n") :name(n), logic_error(s) {}
  string mesg() { return "hmean() invalid arguments: a = -b\n"; }
  virtual ~bad_hmean()throw(){}
private:
  string name;
};
class bad_gmean : public logic_error
{
public:
  explicit bad_gmean(const string& n = "gmean", const string& s = "Error in gmean()\n") :name(n), logic_error(s) {}
  string mesg() { return "gmean() arguments should be >=0\n"; }
  virtual ~bad_gmean()throw() {}
private:
  string name;
};

main:

#include
#include 
#include "exc_mean.h"

using namespace std;

double hmean(double a, double b);
double gmean(double a, double b);
int main()
{
  double x, y, z;
  cout << "Enter two numbers:";
  while (cin>>x>>y)
  {
    try{
      z = hmean(x, y);
      cout << "Harmoni mean of " << x << " and " << y << " is " << z << endl;
      cout << "Geometric mean of " << x << " and " << y << " is " << gmean(x,y) << endl;
    }
    catch(bad_hmean& bg){
      cout << bg.what();
      cout << "Error message:\n" << bg.mesg() << endl;
      cout << "Try again.\n";
      cout << "Enter two numbers:";
      continue;
    }
    catch(bad_gmean& hg){
      cout << hg.what();
      cout << "Error message:\n" << hg.mesg() << endl;
      cout << "Sorry,you don't 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);
}

3.exc_mean.h:

#pragma once
#include 
#include 
#include 
using namespace std;

class exc :public logic_error
{
public:
  explicit exc(double a,double b,const string& n = "exc", const string& s = "Error in exc()\n") :v1(a),v2(b),name(n), logic_error(s) {}
  virtual string mesg() = 0;
  virtual ~exc()throw() {}
  string name;
  double v1;
  double v2;
};
class bad_hmean : public exc
{
public:
  explicit bad_hmean(double a, double b, const string& n = "hmean", const string& s = "Error in hmean()\n") :exc(a,b,n,s) {}
  string mesg() { return "hmean() invalid arguments: "+ to_string(v1) +" = -("+ to_string(v2) +")\n";}
  virtual ~bad_hmean()throw() {}
private:
  string name;
};
class bad_gmean : public exc
{
public:
  explicit bad_gmean(double a, double b, const string& n = "gmean", const string& s = "Error in gmean()\n") :exc(a, b, n, s) {}
  string mesg() { 
    double v = v2;
    if (v1 < 0)
      v = v1;
    return "gmean() arguments "+to_string(v)+" should be >=0\n";
  }
  virtual ~bad_gmean()throw() {}
};

main:

#include
#include 
#include "exc_mean.h"
using namespace std;

double hmean(double a, double b);
double gmean(double a, double b);
int main()
{
  double x, y, z;
  cout << "Enter two numbers:";
  while (cin >> x >> y)
  {
    try {
      z = hmean(x, y);
      cout << "Harmoni mean of " << x << " and " << y << " is " << z << endl;
      cout << "Geometric mean of " << x << " and " << y << " is " << gmean(x, y) << endl;
    }
    catch (bad_hmean& bg) {
      cout << bg.what();
      cout << "Error message:\n" << bg.mesg() << endl;
      cout << "Sorry,you don't get to play any more.\n";
      break;
    }
    catch (bad_gmean& hg) {
      cout << hg.what();
      cout << "Error message:\n" << hg.mesg() << endl;
      cout << "Sorry,you don't get to play any more.\n";
      break;
    }
  }
  cout << "Bye!\n";

  return 0;
}

double hmean(double a, double b) {
  if (a == -b)
    throw bad_hmean(a,b);
  return 2.0 * a*b / (a + b);
}
double gmean(double a, double b) {
  if (a < 0 || b < 0)
    throw bad_gmean(a,b);
  return std::sqrt(a*b);
}

4. sales.h:

#pragma once
#include
#include
using namespace std;
class sales
{
public:
  enum { MONTHS = 12 };
  class bad_index :public logic_error {
  public:
    explicit bad_index(int ix, const char* s = "Index error in Sales object\n"):logic_error(s),bi(ix){}
    int bi_val() { return bi; }
  private:
    int bi;
  };
  explicit sales(int yy = 0);
  sales(int yy, const double* gr, int n);
  int Year()const { return year; }
  virtual double operator[](int i)const throw(logic_error);
  virtual double & operator[](int i)throw(logic_error);
private:
  int year;
  double gross[MONTHS];
};
class LabeldSales:public sales
{
public:
  static const int STRLEN = 50;
  class nbad_index :public sales::bad_index
  {
  public:
    nbad_index(const char* lb, int ix, const char* s = "Index error in LabeldSales object\n");
    const char* label_val() { return lbl; }
  private:
    char lbl[STRLEN];
  };
  explicit LabeldSales(const char* lb = "none", int yy = 0);
  LabeldSales(const char* lb, int yy, const double* gr, int n);
  virtual ~LabeldSales(){}
  const char* Label()const { return label; }
  virtual double operator[](int i)const throw(logic_error);
  virtual double & operator[](int i)throw(logic_error);
private:
  char label[STRLEN];
};

sales.cpp:

#include "sales.h"

sales::sales(int yy):year(yy) {
  for (int i = 0; i < MONTHS; ++i)
    gross[i] = 0;
}

sales::sales(int yy, const double* gr, int n):year(yy) {
  int size = (n< MONTHS)?n:MONTHS;
  int i;
  for(i = 0; i < size; ++i)
    gross[i] = gr[i];
  for (; i < MONTHS; ++i)
    gross[i] = 0;
}
double sales::operator[](int i)const throw(logic_error) {
  if (i < 0 || i >= MONTHS)
    throw bad_index(i);
  return gross[i];
}
double & sales::operator[](int i)throw(logic_error) {
  if (i < 0 || i >= MONTHS)
    throw bad_index(i);
  return gross[i];
}
LabeldSales::nbad_index::nbad_index(const char* lb, int ix, const char* s) :sales::bad_index(ix, s) {  strcpy_s(lbl, STRLEN, lb);}
LabeldSales::LabeldSales(const char* lb, int yy) : sales(yy) {strcpy_s(label, STRLEN, lb);}
LabeldSales::LabeldSales(const char* lb, int yy, const double* gr, int n):sales(yy,gr,n) {strcpy_s(label, STRLEN, lb);}
double LabeldSales::operator[](int i)const throw(logic_error) {
  if (i < 0 || i >= MONTHS)
    throw nbad_index(label,i);
  return sales::operator[](i);
}
double & LabeldSales::operator[](int i)throw(logic_error) {
  if (i < 0 || i >= MONTHS)
    throw nbad_index(label,i);
  return sales::operator[](i);
}

main:

#include
#include "sales.h"

using namespace std;

int main()
{
  double vals1[12] = { 1256,8563,2644,6542,3556,3256,
  6656,8456,3654,3665,3562,4335 };
  double vals2[12] = { 25,36,98,25,32,35,
  28,63,46,86,34,52 };
  sales sales1(2004, vals1, 12);
  LabeldSales sales2("Blogstar", 2005, vals2, 12);
  cout << "Firat try block:\n";
  LabeldSales::nbad_index* nb;
  sales::bad_index* b;
  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 (logic_error& bad) {
    cout << bad.what();
    if (nb = dynamic_cast(&bad)) {
    cout << "Company: " << nb->label_val() << endl;
    cout << "bad index: " << nb->bi_val() << endl;
    }else if(b = dynamic_cast(&bad))
      cout << "bad index: " << b->bi_val() << endl;
  }
  cout << "\nNext try block:\n";
  try {
    sales2[2] = 37.5;
    sales1[20] = 2335;
    cout << "End of try block 2.\n";
  }
  catch (logic_error& bad) {
    cout << bad.what();
    if (nb = dynamic_cast(&bad)) {
      cout << "Company: " << nb->label_val() << endl;
      cout << "bad index: " << nb->bi_val() << endl;
    }
    else if (b = dynamic_cast(&bad))
      cout << "bad index: " << b->bi_val() << endl;
  }

  cout << "done\n";
  return 0;
}