【C++ Primer Plus】编程练习答案——第9章

// chapter09_golf.h

#ifndef LEARN_CPP_CHAPTER09_GOLF_H
#define LEARN_CPP_CHAPTER09_GOLF_H

#include <cstring>
#include <iostream>

const int Len = 40;
struct golf {
    char fullname[Len];
    int handicap;
};

void setgolf(golf &, const char *, int);
int setgolf(golf &);
void handicap(golf &, int);
void showgolf(const golf &);



#endif //LEARN_CPP_CHAPTER09_GOLF_H





// chapter09_golf.cpp

#include "chapter09_golf.h"

void setgolf(golf & g, const char * name, int hc) {
    strcpy(g.fullname, name);
    g.handicap = hc;
}

int setgolf(golf & g) {
    using namespace std;
    cout << "enter name: ";
    cin.getline(g.fullname, Len);
    cout << "enter hc: ";
    cin >> g.handicap;cin.get();
    if (strcmp("\0", g.fullname) == 0)
        return 0;
    return 1;
}

void handicap(golf & g, int hc) {
    g.handicap = hc;
}

void showgolf(const golf & g) {
    using namespace std;
    cout << "name: " << g.fullname << endl;
    cout << "hc: " << g.handicap << endl;
}





// run

void ch9_1() {
    using namespace std;
    golf arr_golf[3];
    cout << "enter golf: ";
    int i;
    for (i = 0; i < 3; ++ i) {
        if (setgolf(arr_golf[i]) == 0)
            break;
    }
    cout << "enter done" << endl;
    for (int j = 0; j < i; ++ j)
        showgolf(arr_golf[j]);
}

void ch9_2_strcount(std::string & str) {
    using namespace std;
    static int total = 0;
    int count = 0;
    cout << "\"" << str << "\" contains ";
    count = str.length();
    total += count;
    cout << count << " chars" << endl;
    cout << total << " chars total" << endl;
}

void ch9_2() {
    using namespace std;
    string str;
    while (true) {
        cout << "enter a line: " << endl;
        getline(cin, str);
        if (str == "")
            break;
        ch9_2_strcount(str);
    }
    cout << "Bye" << endl;
}

void ch9_3() {
    using namespace std;
    int buffer[1000];
    chaff * arr_chaff = new (buffer)chaff[2];
    strcpy(arr_chaff[0].dross, "#1"); arr_chaff[0].slag = 123;
    strcpy(arr_chaff[1].dross, "#2"); arr_chaff[1].slag = 321;
    for (int i = 0; i < 2; ++ i)
        cout << "dross: " << arr_chaff[i].dross << " slag: " << arr_chaff[i].slag << endl;
}

// chapter 09_sales.h

#ifndef LEARN_CPP_CHAPTER09_SALES_H
#define LEARN_CPP_CHAPTER09_SALES_H

#include <iostream>

namespace SALES
{
    const int QUARTERS = 4;
    struct Sales {
        double sales[QUARTERS];
        double average;
        double max;
        double min;
    };
    void setSales(Sales &, const double *, int);
    void setSales(Sales &);
    void showSales(const Sales &);
}



#endif //LEARN_CPP_CHAPTER09_SALES_H







// chapter09_sales.cpp

#include "chapter09_sales.h"

void SALES::setSales(SALES::Sales & s, const double * ar, int n) {
    double sum = 0;
    int p_max = 0, p_min = 0;
    for (int i = 0; i < n; ++ i) {
        s.sales[i] = ar[i];
        sum += ar[i];
        if (ar[i] > ar[p_max])
            p_max = i;
        if (ar[i] < ar[p_min])
            p_min = i;
    }
    s.average = sum / n;
    s.max = ar[p_max];
    s.min = ar[p_min];
}

void SALES::setSales(SALES::Sales & s) {
    using namespace std;
    double sum = 0;
    int p_max = 0, p_min = 0, n = 0;
    for (int i = 0; i < SALES::QUARTERS; ++ i) {
        if (!(cin >> s.sales[i]))
            break;
        cin.get();
        ++ n;
        sum += s.sales[i];
        if (s.sales[i] > s.sales[p_max])
            p_max = i;
        if (s.sales[i] < s.sales[p_min])
            p_min = i;
    }
    s.average = sum / n;
    s.max = s.sales[p_max];
    s.min = s.sales[p_min];
}

void SALES::showSales(const SALES::Sales & s) {
    using namespace std;
    cout << "sales: ";
    for (int i = 0; i < SALES::QUARTERS; ++ i)
        if (s.sales[i])
            cout << s.sales[i];
    cout << endl;
    cout << "average: " << s.average << endl;
    cout << "max: " << s.max << endl;
    cout << "min: " << s.min << endl;
}




// run

void ch9_4() {
    using namespace std;
    SALES::Sales a;
    cout << "set a: " << endl;
    SALES::setSales(a);
    double s[4]{1.1,2.2,3.3,4.4};
    SALES::Sales b;
    SALES::setSales(b,s,4);
    cout << "a: " << endl;
    SALES::showSales(a);
    cout << "b: " << endl;
    SALES::showSales(b);
}