c++ primer plus 习题答案(4)

p333.3

#include<iostream>
#include<cstdlib>
#include<cstring>
#include<string>
using namespace std;

class Golf{
private:
    static const int Len = 40;
    char fullname[Len];
    int handicap;
public:
    Golf(char name[Len], int bt);
    void showgolf() const;
};

void setgolf(char *name, int extent, int &bt){
    cout << "enter a name
";
    cin.get(name, extent);
    while (cin.get() != '
')
        continue;
    cout << "enter a number
";
    cin >> bt;
}

Golf::Golf(char name[Len], int bt){
    strncpy(fullname, name, Len);
    handicap = bt;
}

void Golf::showgolf()const{
    cout << "fullname is " << fullname << endl
        << "handicap is " << handicap;
}

int main(){
    Golf one = Golf("asxc", 5);
    int ct;
    char name[40];
    setgolf(name, 40, ct);
    Golf two = Golf(name, ct);
    one.showgolf();
    cout << endl;
    two.showgolf();

    system("pause");
    return 0;
}

p333.4

//头文件
namespace SALES
{
    class Sales{
    private:
        enum {QUARTERS=4};
        double sales[QUARTERS];
        double average, max, min;
    public:
        Sales();
        Sales(const double *ar, int n);
        void showsales();
    };
}

//方法
#include<iostream>
#include"sales.h"
using namespace std;

SALES::Sales::Sales(){
    cout << "enter four number
";
    double sum = 0;
    for (int i = 0; i < QUARTERS; i++){
        cin >> sales[i];
        sum += sales[i];
    }
    average = sum / QUARTERS;
    max = sales[0];
    min = sales[0];
    for (int i = 1; i < QUARTERS; i++){
        if (max < sales[i])
            max = sales[i];
        if (min>sales[i])
            min = sales[i];
    }
}

SALES::Sales::Sales(const double *ar, int n){
    double sum = 0;
    for (int i = 0; i < n; i++){
        sales[i] = ar[i];
        sum += sales[i];
    }
    average = sum / QUARTERS;
    max = sales[0];
    min = sales[0];
    for (int i = 1; i < QUARTERS; i++){
        if (max < sales[i])
            max = sales[i];
        if (min>sales[i])
            min = sales[i];
    }
}

void SALES::Sales::showsales(){
    cout << "average is " << average << endl
        << "max is " << max << endl
        << "min is " << min;
}

//驱动
#include<iostream>
#include"sales.h"
using namespace std;

int main(){
    using namespace SALES;
    cout << "enter four number
";
    double ar[4];
    for (int i = 0; i < 4; i++)
        cin >> ar[i];
    Sales market1(ar, 4);
    market1.showsales();
    Sales market2;
    cout << endl;
    market2.showsales();

    system("pause");
    return 0;
}

p333.5

//头文件：
#ifndef _STACK_H_
#define _STACK_H_ 

struct customer{
    char fullname[35];
    double payment;
};

typedef customer Item;

class Stack{
private:
    enum{max=10};
    Item items[max];
    int top;
public:
    Stack();
    bool isfull()const;
    bool isempty()const;
    void push(const Item &);
    bool pop(const Item &);
};

#endif

//方法
#include<iostream>
#include"stack.h"
using namespace std;

Stack::Stack(){
    top = 0;
}

bool Stack::isfull()const{
    if (top == max)
        return true;
    else return false;
}

bool Stack::isempty()const{
    if (top == 0)
        return true;
    else return false;
}

void Stack::push(const Item &temp){
    if (isfull())
        cout << "the stack has already full
";
    else items[top++] = temp;
}

bool Stack::pop(const Item &temp){
    if (isempty()){
        cout << "the stack has already empty
";
        return false;
    }
    else {
        items[--top] = temp;
        return true;
    }
}

//驱动：
#include<iostream>
#include"stack.h"
using namespace std;
void get_customer(Item &);

int main(){
    Item temp;
    Stack test;
    double payments=0;
    cout << "enter A to push, enter P to pop or"
        <<"enter Q to quit
";
    char ch;
    while (cin >> ch && (ch != 'Q' && ch != 'q')){
        while (cin.get() != '
')
            continue;
        switch (ch){
        case 'A':
        case 'a':
            get_customer(temp);
            test.push(temp);
            break;
        case 'P':
        case 'p':
            if (test.pop(temp))
                payments += temp.payment;
            cout << "now total payments is " <<
                payments << endl;
        default:
            cout << "please enter A/P or Q
";
        }
        cout << "enter A to push, enter P to pop or"
            << "enter Q to quit
";
    }
    system("pause");
    return 0;    
}

void get_customer(Item &temp){
    cout << "enter a line
";
    cin.getline(temp.fullname, 35);
    cout << "enter a number
";
    cin >> temp.payment;
    cin.get();
}