C++PrimerPlus中文第六版第9章编程练习答案

// golf.h
const int Len = 40;

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

// non-ineractive version:
// function sets golf structure to provided name, handicap
// using values passed as arguments to the function
void setgolf(golf& g, const char* name, int hc);

// interactive version:
// function solicits name and handicap from user
// and sets the member of g to the values entered
// returns 1 if name is entered, 0 if name is empty string
int setgolf(golf& g);
// function resets handicap to new value
void handicap(golf& g, int hc);

// function display contents of golf structure
void showgolf(const golf& g);

// golf.cpp
#include<iostream>
#include"golf.h"

void setgolf(golf& g, const char* name, int hc)
{
    strcpy_s(g.fullname, name);
    g.handicap = hc;
}
int setgolf(golf& g)
{
    using namespace std;
    cout << "Enter the full name: ";
    cin.getline(g.fullname, Len);
    cout << "Enter the handicap: ";
    cin >> g.handicap;
    cin.clear();
    while (cin.get() != '\n');
    if (strlen(g.fullname) == 0)
    {
        cout << "The fullname is empty!\n";
        return 0;
    }
    else
    {
        return 1;
    }
}
void handicap(golf& g, int hc)
{
    g.handicap = hc;
}
void showgolf(const golf& g)
{
    using std::cout;
    using std::endl;
    cout << "fullname: " << g.fullname;
    cout << ", handicap: " << g.handicap << endl;
}

// main.cpp
#include<iostream>
#include<string>
#include"golf.h"

const int N = 10;
const int hcLimit = 5;

int main()
{
    using namespace std;
    srand(time(0));
    int i;
    golf golfers[N];
    int hc;
    for (int i = 0; i < N; i++)
    {
        char id[5];
        _itoa_s(i, id, 10);
        char name[Len] = "golfer#";
        strcat_s(name, id);
        hc = rand() % hcLimit;
        setgolf(golfers[i], name, hc);
    }
    for (int i = 0; i < N; i++)
        showgolf(golfers[i]);
    
    for (i = 0; i < N; i++)
    {
        if (!setgolf(golfers[i]))
            break;
    }
    for (int j = 0; j < i; j++)
        showgolf(golfers[j]);

}

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

void strcount(const string& s);


int main()
{
    string input;
    cout << "Enter a line:\n";
    getline(cin, input);
    while (input != "")
    {
        strcount(input);
        cout << "Enter next line (empty to quit):\n";
        getline(cin, input);
    }
    cout << "Bye.\n";
}

void strcount(const string& str)
{
    static int total = 0;
    int count = 0;
    count += str.length();
    total += str.length();
    cout << "\"" << str << "\" contains " << count <<" characters. " << total<<" characters total.\n";

}

#include<iostream>

const int BUF = 48;
const int N = 10;
const int S = 100;

struct chaff
{
    char dross[20];
    int slag;
};

char buffer[BUF];

void setchaff(chaff* pcha, int n);
void showchaff(const chaff* pcha, int n);

int main()
{
    // 使用静态数组作为缓冲区
    chaff* pcha = new (buffer) chaff[2];
    setchaff(pcha, 2);
    showchaff(pcha, 2);
    // 使用new运算符分配缓冲区
    chaff* pcha1 = new chaff[2];
    setchaff(pcha, 2);
    showchaff(pcha, 2);
    delete[] pcha1;
}

void showchaff(const chaff* pcha, int n)
{
    using namespace std;
    for (int i = 0; i < n; i++)
    {
        cout << "dross: " << pcha[i].dross << ", slag: " << pcha[i].slag << endl;
    }
}
void setchaff(chaff* pcha, int n)
{
    using namespace std;
    srand(time(0));
    for (int i = 0; i < n; i++)
    {
        char id[N];
        _itoa_s(i, id, 10);
        char dross[20] = "chaff#";
        strcat_s(dross, id);
        strcpy_s(pcha[i].dross, dross);
        pcha[i].slag = rand() % S;
    }
}

// sales.h
namespace SALES
{
    const int QUARTERS = 4;
    struct Sales
    {
        double sales[QUARTERS];
        double average; 
        double max;
        double min;
    };
    // copies the lesser of 4 or n items from the array ar
    // to the sales number of s and computers and sotores the
    // average, maximum, and minimum values of the entered items;
    // remaining elements of sales, if any, set to 0
    void setSales(Sales& s, const double ar[], int n);
    // gathers sales for 4 quaters interactively, stores them
    // in the sales member of s and computes and stores the 
    //average, maximum, and minimum values
    void setSales(Sales& s);
    // display all information in structure s
    void showSales(const Sales& s);
}

/ sales.cpp
#include<iostream>
#include"sales.h"

namespace SALES
{
    void setSales(Sales& s, const double ar[], int n)
    {
        int i;
        for (i = 0; i < n; i++)
            s.sales[i] = ar[i];
        while (i < 4)
            s.sales[i++] = 0;
        double max=s.sales[0], min=s.sales[0], total=s.sales[0];
        for (i = 1; i < 4; i++)
        {
            total += s.sales[i];
            if (s.sales[i] > max)
                max = s.sales[i];
            if (s.sales[i] < min)
                min = s.sales[i];
        }
        s.average = total / 4;
        s.max = max;
        s.min = min;
    }
    void setSales(Sales& s)
    {
        using namespace std;
        for (int i = 0; i < 4; i++)
        {
            cout << "sales #" << i + 1 << " quarter: ";
            cin >> s.sales[i];
        }
        double max = s.sales[0], min = s.sales[0], total = s.sales[0];
        for (int i = 1; i < 4; i++)
        {
            total += s.sales[i];
            if (s.sales[i] > max)
                max = s.sales[i];
            if (s.sales[i] < min)
                min = s.sales[i];
        }
        s.average = total / 4;
        s.max = max;
        s.min = min;
    }
    void showSales(const Sales& s)
    {
        using namespace std;
        for (int i = 0; i < 4; i++)
            cout << "quarter #" << i + 1 << ": " << s.sales[i] << endl;
        cout << "max: " << s.max << ", min: " << s.min << ", average: " << s.average << endl;
    }
}

// main.cpp
#include<iostream>
#include"sales.h"

int main()
{
    using namespace SALES;
    Sales s;
    double sales[3] = { 1234.2, 2345.3, 3456.4 };
    setSales(s, sales, 3);
    showSales(s);
    setSales(s);
    showSales(s);
}