c++ primer plus 习题答案(5)

p333.7

 1 #include<iostream>

 2 #include<cstring>

 3 #include<cstdlib>

 4 using namespace std;

 5 

 6 class Plorg{

 7 private:

 8     char fullname[19];

 9     int CI;

10 public:

11     Plorg(char *ar = "Plorga", int ct = 50);

12     void index();

13     void show()const;

14 };

15 

16 Plorg::Plorg(char *ar, int ct){

17     strcpy(fullname, ar);

18     CI = ct;

19 }

20 

21 void Plorg::index(){

22     cout << "enter a number of CI\n";

23     cin >> CI;

24 }

25 

26 void Plorg::show()const{

27     cout << "fullname is " << this->fullname <<

28         " CI is " << (*this).CI << endl;

29 }

30 

31 int main(){

32     Plorg test1;

33     cout << "enter a line\n";

34     char ar[19];

35     int ct;

36     cin.getline(ar, 19);

37     cout << "enter a number\n";

38     cin >> ct;

39     cin.get();

40     Plorg test2(ar, ct);

41     test1.show();

42     cout << endl;

43     test2.show();

44     test1.index();

45     cout << endl;

46     test1.show();

47 

48     system("pause");

49     return 0;

50 }

p375.5

  1 //头文件：

  2 #include<iostream>

  3 

  4 #ifndef _STONEWT_H

  5 #define _STONEWT_H

  6 class Stonewt{

  7 private:

  8     static const int lbs_per_stn = 14;

  9     int stone;

 10     double pds_left;

 11     double pounds;

 12     char mode;

 13 public:

 14     Stonewt();

 15     Stonewt(double, char ch='P');

 16     Stonewt(int, double, char ch='P');

 17     ~Stonewt();

 18     void set(Stonewt &);

 19     void mode_invert(char);

 20     Stonewt operator+(const Stonewt & a)const 

 21     {return Stonewt(pounds + a.pounds); }

 22     friend Stonewt operator-(const Stonewt &, const Stonewt &);

 23     friend Stonewt operator*(double n, const Stonewt &);

 24     friend std::ostream & operator<<(std::ostream &, const Stonewt &);

 25 };

 26 

 27 #endif

 28 

 29 //方法：

 30 #include<iostream>

 31 #include"stack.h"

 32 using std::cout;

 33 using std::cin;

 34 using std::endl;

 35 

 36 Stonewt::Stonewt(){

 37     pds_left = pounds = stone = 0;

 38     mode = 'P';

 39 }

 40 

 41 Stonewt::Stonewt(double a, char ch){

 42     pounds = a;

 43     stone = int(a / lbs_per_stn);

 44     pds_left = pounds - stone*lbs_per_stn;

 45     mode = ch;

 46 }

 47 

 48 Stonewt::Stonewt(int a, double b, char ch){

 49     pounds = a*lbs_per_stn + b;

 50     stone = a + int(b / lbs_per_stn);

 51     pds_left = pounds - stone*lbs_per_stn;

 52     mode = ch;

 53 }

 54 

 55 void Stonewt::set(Stonewt &a){

 56     cout << "enter stone\n";

 57     cin >> a.stone;

 58     cout << "enter pounds\n";

 59     cin >> a.pds_left;

 60     a.pounds = a.stone*lbs_per_stn + a.pds_left;

 61     cout << "enter a mode that you want to choice\n";

 62     cin >> a.mode;

 63 }

 64 

 65 

 66 Stonewt::~Stonewt(){

 67 

 68 }

 69 

 70 Stonewt operator-(const Stonewt &a, const Stonewt &b){

 71     Stonewt sum;

 72     sum = a + b;

 73     return sum;

 74 }

 75 

 76 Stonewt operator*(double n, const Stonewt &a){

 77     return Stonewt(n*a.pounds);

 78 }

 79 

 80 std::ostream & operator<<(std::ostream &os, const Stonewt &t){

 81     if (t.mode == 'P')

 82         cout << "pounds is " << t.pounds;

 83     else if (t.mode == 'S')

 84         cout << "stone is " << t.stone << " pds_left is " << t.pds_left << endl;

 85     else cout << "wrong choices\n";

 86     return os;

 87 }

 88 

 89 //驱动：

 90 #include<iostream>

 91 #include<cstdlib>

 92 #include"stack.h"

 93 using std::cout;

 94 using std::endl;

 95 

 96 int main(){

 97     Stonewt ct(54.6, 'S');

 98     Stonewt bt(23, 56.3, 'P');

 99     Stonewt at;

100     Stonewt dt = bt + ct;

101     Stonewt ft = bt - ct;

102     int n = 4;

103     Stonewt gt = n*bt;

104     cout << ct << endl << bt << endl

105         << dt << endl << ft << endl

106         << gt << endl<<at;

107 

108     system("pause");

109     return 0;

110 }

p375.7

  1 //头文件：

  2 #include<iostream>

  3 

  4 #ifndef _COMPLEX_H

  5 #define _COMPLEX_H

  6 

  7 using std::ostream;

  8 using std::istream;

  9 

 10 namespace COMPLEX{

 11     class Complex{

 12     private:

 13         double real;

 14         double imaginary;

 15     public:

 16         Complex();

 17         Complex(double, double);

 18         Complex operator+(const Complex &);

 19         Complex operator-(const Complex &);

 20         friend Complex operator*(const Complex &, const Complex &);

 21         friend Complex operator*(const Complex &, const double);

 22         friend Complex operator~(const Complex &);

 23         friend ostream & operator<<(ostream &, const Complex &);

 24         friend istream & operator>>(istream &, Complex &);

 25     };

 26 }

 27 

 28 #endif

 29 

 30 //方法：

 31 #include<iostream>

 32 using namespace std;

 33 #include"stack.h"

 34 

 35 namespace COMPLEX{

 36     Complex::Complex(){

 37         real = imaginary = 0;

 38     }

 39 

 40     Complex::Complex(double a, double b){

 41         real = a;

 42         imaginary = b;

 43     }

 44 

 45     Complex Complex::operator+(const Complex &a){

 46         return Complex(real + a.real, imaginary + a.imaginary);

 47     }

 48 

 49     Complex Complex::operator-(const Complex &a){

 50         return Complex(real - a.real, imaginary - a.imaginary);

 51     }

 52 

 53     Complex operator*(const Complex &a, const Complex &b){

 54         return Complex(a.real*b.real - a.imaginary*b.imaginary, a.real*b.imaginary + a.imaginary*b.real);

 55     }

 56 

 57     Complex operator*(const Complex &a, const double b){

 58         return Complex(a.real*b, a.imaginary*b);

 59     }

 60 

 61     Complex operator~(const Complex &a){

 62         return Complex(a.real, -a.imaginary);

 63     }

 64 

 65     ostream & operator<<(ostream &os, const Complex &b){

 66         cout << "(" << b.real << ", " << b.imaginary << "i)";

 67         return os;

 68     }

 69 

 70     istream & operator>>(istream &is, Complex &a){

 71         if (is >> a.real){

 72             is >> a.imaginary;

 73             cout << "real: " << a.real << endl;

 74             cout << "imaginary: " << a.imaginary << endl;

 75         }

 76         return is;

 77     }

 78 }

 79 

 80 //驱动：

 81 #include<iostream>

 82 using namespace std;

 83 #include"stack.h"

 84 using namespace COMPLEX;

 85 

 86 int main(){

 87     Complex a(3.0, 4.0);

 88     Complex c;

 89     cout << "enter a complex number(q to quit)\n";

 90     while (cin>>c){

 91         cout << "c is " << c << endl;

 92         cout << "complex conjugate is " << ~c << endl;

 93         cout << "a is " << a << endl;

 94         cout << "a+c  is " << a + c << endl;

 95         cout << "a-c is " << a - c << endl;

 96         cout << "a*c is " << a*c << endl;

 97         cout << "2*c is " << c*2 << endl;

 98         cout << "enter a complex number(q to quit)\n";

 99     }

100     cout << "Done!\n";

101     system("pause");

102     return 0;

103 }