c++ primer plus 习题答案(5)

p333.7

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

class Plorg{
private:
    char fullname[19];
    int CI;
public:
    Plorg(char *ar = "Plorga", int ct = 50);
    void index();
    void show()const;
};

Plorg::Plorg(char *ar, int ct){
    strcpy(fullname, ar);
    CI = ct;
}

void Plorg::index(){
    cout << "enter a number of CI
";
    cin >> CI;
}

void Plorg::show()const{
    cout << "fullname is " << this->fullname <<
        " CI is " << (*this).CI << endl;
}

int main(){
    Plorg test1;
    cout << "enter a line
";
    char ar[19];
    int ct;
    cin.getline(ar, 19);
    cout << "enter a number
";
    cin >> ct;
    cin.get();
    Plorg test2(ar, ct);
    test1.show();
    cout << endl;
    test2.show();
    test1.index();
    cout << endl;
    test1.show();

    system("pause");
    return 0;
}

p375.5

//头文件：
#include<iostream>

#ifndef _STONEWT_H
#define _STONEWT_H
class Stonewt{
private:
    static const int lbs_per_stn = 14;
    int stone;
    double pds_left;
    double pounds;
    char mode;
public:
    Stonewt();
    Stonewt(double, char ch='P');
    Stonewt(int, double, char ch='P');
    ~Stonewt();
    void set(Stonewt &);
    void mode_invert(char);
    Stonewt operator+(const Stonewt & a)const 
    {return Stonewt(pounds + a.pounds); }
    friend Stonewt operator-(const Stonewt &, const Stonewt &);
    friend Stonewt operator*(double n, const Stonewt &);
    friend std::ostream & operator<<(std::ostream &, const Stonewt &);
};

#endif

//方法：
#include<iostream>
#include"stack.h"
using std::cout;
using std::cin;
using std::endl;

Stonewt::Stonewt(){
    pds_left = pounds = stone = 0;
    mode = 'P';
}

Stonewt::Stonewt(double a, char ch){
    pounds = a;
    stone = int(a / lbs_per_stn);
    pds_left = pounds - stone*lbs_per_stn;
    mode = ch;
}

Stonewt::Stonewt(int a, double b, char ch){
    pounds = a*lbs_per_stn + b;
    stone = a + int(b / lbs_per_stn);
    pds_left = pounds - stone*lbs_per_stn;
    mode = ch;
}

void Stonewt::set(Stonewt &a){
    cout << "enter stone
";
    cin >> a.stone;
    cout << "enter pounds
";
    cin >> a.pds_left;
    a.pounds = a.stone*lbs_per_stn + a.pds_left;
    cout << "enter a mode that you want to choice
";
    cin >> a.mode;
}


Stonewt::~Stonewt(){

}

Stonewt operator-(const Stonewt &a, const Stonewt &b){
    Stonewt sum;
    sum = a + b;
    return sum;
}

Stonewt operator*(double n, const Stonewt &a){
    return Stonewt(n*a.pounds);
}

std::ostream & operator<<(std::ostream &os, const Stonewt &t){
    if (t.mode == 'P')
        cout << "pounds is " << t.pounds;
    else if (t.mode == 'S')
        cout << "stone is " << t.stone << " pds_left is " << t.pds_left << endl;
    else cout << "wrong choices
";
    return os;
}

//驱动：
#include<iostream>
#include<cstdlib>
#include"stack.h"
using std::cout;
using std::endl;

int main(){
    Stonewt ct(54.6, 'S');
    Stonewt bt(23, 56.3, 'P');
    Stonewt at;
    Stonewt dt = bt + ct;
    Stonewt ft = bt - ct;
    int n = 4;
    Stonewt gt = n*bt;
    cout << ct << endl << bt << endl
        << dt << endl << ft << endl
        << gt << endl<<at;

    system("pause");
    return 0;
}

p375.7

//头文件：
#include<iostream>

#ifndef _COMPLEX_H
#define _COMPLEX_H

using std::ostream;
using std::istream;

namespace COMPLEX{
    class Complex{
    private:
        double real;
        double imaginary;
    public:
        Complex();
        Complex(double, double);
        Complex operator+(const Complex &);
        Complex operator-(const Complex &);
        friend Complex operator*(const Complex &, const Complex &);
        friend Complex operator*(const Complex &, const double);
        friend Complex operator~(const Complex &);
        friend ostream & operator<<(ostream &, const Complex &);
        friend istream & operator>>(istream &, Complex &);
    };
}

#endif

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

namespace COMPLEX{
    Complex::Complex(){
        real = imaginary = 0;
    }

    Complex::Complex(double a, double b){
        real = a;
        imaginary = b;
    }

    Complex Complex::operator+(const Complex &a){
        return Complex(real + a.real, imaginary + a.imaginary);
    }

    Complex Complex::operator-(const Complex &a){
        return Complex(real - a.real, imaginary - a.imaginary);
    }

    Complex operator*(const Complex &a, const Complex &b){
        return Complex(a.real*b.real - a.imaginary*b.imaginary, a.real*b.imaginary + a.imaginary*b.real);
    }

    Complex operator*(const Complex &a, const double b){
        return Complex(a.real*b, a.imaginary*b);
    }

    Complex operator~(const Complex &a){
        return Complex(a.real, -a.imaginary);
    }

    ostream & operator<<(ostream &os, const Complex &b){
        cout << "(" << b.real << ", " << b.imaginary << "i)";
        return os;
    }

    istream & operator>>(istream &is, Complex &a){
        if (is >> a.real){
            is >> a.imaginary;
            cout << "real: " << a.real << endl;
            cout << "imaginary: " << a.imaginary << endl;
        }
        return is;
    }
}

//驱动：
#include<iostream>
using namespace std;
#include"stack.h"
using namespace COMPLEX;

int main(){
    Complex a(3.0, 4.0);
    Complex c;
    cout << "enter a complex number(q to quit)
";
    while (cin>>c){
        cout << "c is " << c << endl;
        cout << "complex conjugate is " << ~c << endl;
        cout << "a is " << a << endl;
        cout << "a+c  is " << a + c << endl;
        cout << "a-c is " << a - c << endl;
        cout << "a*c is " << a*c << endl;
        cout << "2*c is " << c*2 << endl;
        cout << "enter a complex number(q to quit)
";
    }
    cout << "Done!
";
    system("pause");
    return 0;
}