c++ primer plus 第九章答案

1.

main.cpp

#include <iostream>#include "golf.h"using namespace std;int main(){    golf test[5];    golf otherone;    for(int i = 0; i < 5; i++)    {        if(!setgolf(test[i]))            return 0;    }    setgolf(otherone, "hello world!", 3);    showgolf(otherone);    handicap(otheone, 888);    showgolf();}

golf.h

#ifndef GOLF_H_INCLUDED#define GOLF_H_INCLUDEDconst int Len = 40;struct golf{    char fullname[Len];    int handicap;};void setgolf(golf & g, const char * name, int hc);int setgolf(golf & g);void handicap(golf & g, int hc);void showgolf(const golf & g);#endif // GOLF_H_INCLUDED

golf.cpp

#include <iostream>#include "golf.h"#include <cstring>using namespace std;void setgolf(golf & g, const char * name, int hc){    strcpy(g.fullname, name);    g.handicap = hc;}int setgolf(golf & g){    cout << "Please enter the fullname";    if(cin.getline(g.fullname,40) && strlen(g.fullname) != 0)    {        cout << "Please enter the number";        cin >> g.handicap;        cin.get();        return 1;    }    else    {        cout << "error";        return 0;    }}void handicap(golf & g, int hc){    g.handicap = hc;}void showgolf(const golf & g){    cout << g.fullname << ' ';    cout << g.handicap;    cout << endl;}

2.

#include <iostream>#include <string>using namespace std;void strcount(const string input);int main(){    string input;    char next;    cout << "enter a line:\n";    getline(cin, input);    while(cin)    {        strcount(input);        cout << "Enter next line";        getline(cin, input);    }    cout << "bye\n";    return 0;}void strcount(const string input){    using namespace std;    static int total = 0;    int count = 0;    if(input == "")        cout << "It's blank!!!";    else        {            cout << "\"" << input << "\" contains ";            cout << input.length() << " letters" << endl;        }}

3.方法1

#include <iostream>#include <new>using namespace std;struct chaff{    char dross[20];    int slag;};char buffer[512];int main(){    chaff * test = new(buffer) chaff[2];    for(int i = 0; i < 2; i++)    {        cin.getline(test[i].dross,20);        cin >> test[i].slag;        cin.get();    }    for(int i = 0; i < 2; i++)        cout << test[i].dross << ' ' << test[i].slag << endl

}

方法2：

#include <iostream>#include <new>using namespace std;struct chaff{    char dross[20];    int slag;};int main(){    chaff * test = new chaff[2];    for(int i = 0; i < 2; i++)    {        cin.getline(test[i].dross,20);        cin >> test[i].slag;        cin.get();    }    for(int i = 0; i < 2; i++)    {        cout << test[i].dross << ' ' << test[i].slag << endl;    }    return 0;}

4.main.cpp

#include <iostream>#include "sale.h"int main(){    double a[3] = {1.1, 2.2, 3.3};    SALES::Sales s;    SALES::setSales(s, a, 3);    SALES::showSales(s);    SALES::setSales(s);    SALES::showSales(s);    return 0;}

sale.h

#ifndef SALE_H_INCLUDED#define SALE_H_INCLUDEDnamespace SALES{    const int QUARTERS = 4;    struct Sales    {        double sales[QUARTERS];        double average;        double max;        double min;    };    void setSales(Sales & s, const double ar[], int n);    void setSales(Sales & s);    void showSales(const Sales & s);}#endif // SALE_H_INCLUDED

sale.cpp

#include "sale.h"#include <iostream>using namespace std;namespace SALES{    void setSales(Sales & s, const double ar[], int n)    {        int sum = 0;        int avg, max ,min;        for(int i = 0; i < n; i++)        {            s.sales[i] = ar[i];            sum += s.sales[i];        }        max = min = s.sales[0];        for(int i = 1; i < n; i++)        {            max = max > s.sales[i] ? max : s.sales[i];            min = min < s.sales[i] ? min : s.sales[i];        }        avg = sum / n;    }    void setSales(Sales & s)    {        double max = 999;        double min = -999;        double avg = 0;        for(int i = 0 ; i < 4 ; ++i)        {            cin >> s.sales[i];            max = max < s.sales[i] ? s.sales[i] : max;            min = min > s.sales[i] ? s.sales[i] : min;            avg += s.sales[i];        }        s.max = max;        s.min = min;        s.average = avg / 4;    }    void showSales(const Sales & s)    {        for(int i = 0 ; i < 4 ; ++i)            cout << s.sales[i] << endl;        cout << "MAX: " << s.max << endl << "MIN: " << s.min  << endl << "AVE: " << s.average << endl;    }}