C++ Primer Plus第五版 第九章 编程练习答案

/*******************************************************************************************************************   Author : Cui mingyang  Blog : cx_12586  Time : 2017/10/30  From : C++ Primer Plus第五版第9章编程练习 第1题   *******************************************************************************************************************/   #include <iostream>    #include "golf.h"   using namespace std;  int main()    {        golf Ann;        setgolf(Ann);        showgolf(Ann);        setgolf(Ann, "Ann Birdfree", 24);      cout << "The recorded name and handicap are: \n";      showgolf(Ann);        handicap(Ann, 66);        cout << "Your amended name and handicap are: \n";      showgolf(Ann);       system("pause");      return 0;    }      #ifndef GOLF_H_  #define GOLF_H_  const int Len = 40;    struct golf  {        char fullname[Len];        int handicap;    };      void setgolf(golf &g, const char *name, int hc);    int setgolf(golf &g);    void handicap(golf &g, int hc);    void showgolf(const golf &g);   #endif    #include "golf.h"  #include<iostream>  #include<cstring>  using namespace std;  void setgolf(golf &Ann, const char *name, int hc)  {      strcpy(Ann.fullname, name);        Ann.handicap = hc;    }    int setgolf(golf &Ann)  {      cout << "Please enter your name: ";      cin.getline(Ann.fullname, Len);       cout << "Please enter your handicap: ";      cin >> Ann.handicap;        return Ann.fullname == NULL ? 0 : 1;   }    void handicap(golf &Ann, int hc)  {      Ann.handicap = hc;    }    void showgolf(const golf &Ann)  {      cout << Ann.fullname << endl;      cout << Ann.handicap << endl;    }

/*******************************************************************************************************************   Author : Cui mingyang  Blog : cx_12586  Time : 2017/10/30  From : C++ Primer Plus第五版第9章编程练习 第2题   *******************************************************************************************************************/   #include <iostream>    #include <string>      void strcount(const std::string &s);      int main()    {        std::string s;        while(getline(std::cin, s))            strcount(s);        system("pause");      return 0;    }      void strcount(const std::string &s)    {        static int total = 0;        int len = 0;        for(int i = 0 ; i < (int)s.length() ; ++i)            len += s[i] == ' ' ? 0 : 1;        std::cout << len << std::endl;        total += len;        std::cout << "Total: " << total << std::endl;    }

/*******************************************************************************************************************   Author : Cui mingyang  Blog : cx_12586  Time : 2017/10/30  From : C++ Primer Plus第五版第9章编程练习 第3题   *******************************************************************************************************************/   // newplace.cpp -- using placement new  #include <iostream>  #include <new>         // for placement new    struct chaff  {      char dross[20];      int slag;  };  const int BUF = 512;  const int N = 5;  char Buffer[BUF];      // chunk of memory  int main()  {      using namespace std;      cout << "Calling new and placement new:\n";      chaff *p = new (Buffer) chaff[2];        for(int i = 0 ; i < 2 ; ++i)        {            std::cin.getline(p[i].dross, 20);            std::cin >> p[i].slag; std::cin.get(); //吸收'\n'        }        for(int i = 0 ; i < 2 ; ++i)            std::cout << "#" << i + 1 << std::endl << p[i].dross << std::endl << p[i].slag << std::endl;        delete p;      system("pause");      return 0;  } 

/*******************************************************************************************************************   Author : Cui mingyang  Blog : cx_12586  Time : 2017/10/30  From : C++ Primer Plus第五版第9章编程练习 第4题   *******************************************************************************************************************/   #include <iostream>  #include "sale.h"  int main()  {      double a[3] = {1.1, 2.2, 3.3};      SALES::Sales s;      SALES::setSales(s, a, 3);      SALES::showSales(s);      SALES::setSales(s);      SALES::showSales(s);      system("pause");      return 0;  }  namespace SALES  {      const int QUARTERS = 4;      struct Sales      {          double sales[QUARTERS];          double average;          double max;          double min;      };      void setSales(Sales &s, const double ar[], int n);      void setSales(Sales &s);      void showSales(const Sales &s);  }  #include <iostream>  #include "sale.h"    namespace SALES  {      void setSales(Sales &s, const double ar[], int n)      {          double max = -1, min = 999999, average = 0;          if(n < 4)          {              for(int i = 0 ; i < 4 ; ++i)              {                  if(i < n)                  {                      s.sales[i] = ar[i];                      max = max < s.sales[i] ? s.sales[i] : max;                      min = min > s.sales[i] ? s.sales[i] : min;                      average += s.sales[i];                  }                  else                      s.sales[i] = 0;              }              s.max = max;              s.min = min;              s.average = average / n;          }          else          {              for(int i = 0 ; i < 4 ; ++i)              {                  s.sales[i] = ar[i];                  max = max < s.sales[i] ? s.sales[i] : max;                  min = min > s.sales[i] ? s.sales[i] : min;                  average += s.sales[i];              }              s.max = max;              s.min = min;              s.average = average / 4;          }      }        void setSales(Sales &s)      {          double max = -1, min = 999999, average = 0;          for(int i = 0 ; i < 4 ; ++i)          {              std::cin >> s.sales[i];              max = max < s.sales[i] ? s.sales[i] : max;              min = min > s.sales[i] ? s.sales[i] : min;              average += s.sales[i];          }          s.max = max;          s.min = min;          s.average = average / 4;      }        void showSales(const Sales &s)      {          for(int i = 0 ; i < 4 ; ++i)              std::cout << s.sales[i] << std:: endl;          std::cout << "MAX: " << s.max << std::endl << "MIN: " << s.min  << std:: endl << "AVE: " << s.average << std::endl;      }}