c++ primer plus 习题答案(4)

 1 #include<iostream>
 2 #include<cstdlib>
 3 #include<cstring>
 4 #include<string>
 5 using namespace std;
 6 
 7 class Golf{
 8 private:
 9     static const int Len = 40;
10     char fullname[Len];
11     int handicap;
12 public:
13     Golf(char name[Len], int bt);
14     void showgolf() const;
15 };
16 
17 void setgolf(char *name, int extent, int &bt){
18     cout << "enter a name\n";
19     cin.get(name, extent);
20     while (cin.get() != ‘\n‘)
21         continue;
22     cout << "enter a number\n";
23     cin >> bt;
24 }
25 
26 Golf::Golf(char name[Len], int bt){
27     strncpy(fullname, name, Len);
28     handicap = bt;
29 }
30 
31 void Golf::showgolf()const{
32     cout << "fullname is " << fullname << endl
33         << "handicap is " << handicap;
34 }
35 
36 int main(){
37     Golf one = Golf("asxc", 5);
38     int ct;
39     char name[40];
40     setgolf(name, 40, ct);
41     Golf two = Golf(name, ct);
42     one.showgolf();
43     cout << endl;
44     two.showgolf();
45 
46     system("pause");
47     return 0;
48 }

 1 //头文件
 2 namespace SALES
 3 {
 4     class Sales{
 5     private:
 6         enum {QUARTERS=4};
 7         double sales[QUARTERS];
 8         double average, max, min;
 9     public:
10         Sales();
11         Sales(const double *ar, int n);
12         void showsales();
13     };
14 }
15 
16 //方法
17 #include<iostream>
18 #include"sales.h"
19 using namespace std;
20 
21 SALES::Sales::Sales(){
22     cout << "enter four number\n";
23     double sum = 0;
24     for (int i = 0; i < QUARTERS; i++){
25         cin >> sales[i];
26         sum += sales[i];
27     }
28     average = sum / QUARTERS;
29     max = sales[0];
30     min = sales[0];
31     for (int i = 1; i < QUARTERS; i++){
32         if (max < sales[i])
33             max = sales[i];
34         if (min>sales[i])
35             min = sales[i];
36     }
37 }
38 
39 SALES::Sales::Sales(const double *ar, int n){
40     double sum = 0;
41     for (int i = 0; i < n; i++){
42         sales[i] = ar[i];
43         sum += sales[i];
44     }
45     average = sum / QUARTERS;
46     max = sales[0];
47     min = sales[0];
48     for (int i = 1; i < QUARTERS; i++){
49         if (max < sales[i])
50             max = sales[i];
51         if (min>sales[i])
52             min = sales[i];
53     }
54 }
55 
56 void SALES::Sales::showsales(){
57     cout << "average is " << average << endl
58         << "max is " << max << endl
59         << "min is " << min;
60 }
61 
62 //驱动
63 #include<iostream>
64 #include"sales.h"
65 using namespace std;
66 
67 int main(){
68     using namespace SALES;
69     cout << "enter four number\n";
70     double ar[4];
71     for (int i = 0; i < 4; i++)
72         cin >> ar[i];
73     Sales market1(ar, 4);
74     market1.showsales();
75     Sales market2;
76     cout << endl;
77     market2.showsales();
78 
79     system("pause");
80     return 0;
81 }

  1 //头文件：
  2 #ifndef _STACK_H_
  3 #define _STACK_H_ 
  4 
  5 struct customer{
  6     char fullname[35];
  7     double payment;
  8 };
  9 
 10 typedef customer Item;
 11 
 12 class Stack{
 13 private:
 14     enum{max=10};
 15     Item items[max];
 16     int top;
 17 public:
 18     Stack();
 19     bool isfull()const;
 20     bool isempty()const;
 21     void push(const Item &);
 22     bool pop(const Item &);
 23 };
 24 
 25 #endif
 26 
 27 //方法
 28 #include<iostream>
 29 #include"stack.h"
 30 using namespace std;
 31 
 32 Stack::Stack(){
 33     top = 0;
 34 }
 35 
 36 bool Stack::isfull()const{
 37     if (top == max)
 38         return true;
 39     else return false;
 40 }
 41 
 42 bool Stack::isempty()const{
 43     if (top == 0)
 44         return true;
 45     else return false;
 46 }
 47 
 48 void Stack::push(const Item &temp){
 49     if (isfull())
 50         cout << "the stack has already full\n";
 51     else items[top++] = temp;
 52 }
 53 
 54 bool Stack::pop(const Item &temp){
 55     if (isempty()){
 56         cout << "the stack has already empty\n";
 57         return false;
 58     }
 59     else {
 60         items[--top] = temp;
 61         return true;
 62     }
 63 }
 64 
 65 //驱动：
 66 #include<iostream>
 67 #include"stack.h"
 68 using namespace std;
 69 void get_customer(Item &);
 70 
 71 int main(){
 72     Item temp;
 73     Stack test;
 74     double payments=0;
 75     cout << "enter A to push, enter P to pop or"
 76         <<"enter Q to quit\n";
 77     char ch;
 78     while (cin >> ch && (ch != ‘Q‘ && ch != ‘q‘)){
 79         while (cin.get() != ‘\n‘)
 80             continue;
 81         switch (ch){
 82         case ‘A‘:
 83         case ‘a‘:
 84             get_customer(temp);
 85             test.push(temp);
 86             break;
 87         case ‘P‘:
 88         case ‘p‘:
 89             if (test.pop(temp))
 90                 payments += temp.payment;
 91             cout << "now total payments is " <<
 92                 payments << endl;
 93         default:
 94             cout << "please enter A/P or Q\n";
 95         }
 96         cout << "enter A to push, enter P to pop or"
 97             << "enter Q to quit\n";
 98     }
 99     system("pause");
100     return 0;    
101 }
102 
103 void get_customer(Item &temp){
104     cout << "enter a line\n";
105     cin.getline(temp.fullname, 35);
106     cout << "enter a number\n";
107     cin >> temp.payment;
108     cin.get();
109 }