实验一

 

#include<iostream>
#include<math.h>
using namespace std;
class Complex
{
public:
    Complex(double r=0,const double i=0)
    {
        real=r;
        imag=i;
    }
    Complex(const Complex &p);
    double get_real();
    double get_imag() const;
    void show() const;
    void add(const Complex &c1);    
    friend Complex add(const Complex &c2,const Complex &c3);
    friend bool is_equal(const Complex &c4,const Complex &c5);
    friend double abs(const Complex c6);
private:
    double real,imag;
};
Complex::Complex(const Complex &p)
{
    real=p.real;
    imag=p.imag;
}
double Complex::get_real()
{
    return real;
}
double Complex::get_imag ()const
{
    return imag;
}
void Complex::show() const
{
    if(imag>0)
        cout<<real<<"+"<<imag<<"i"<<endl;
    else if(imag==0)
        cout<<real<<endl;
    else 
        cout<<real<<imag<<"i"<<endl;
}
void Complex::add(const Complex &c1)
{
    real+=c1.real;
    imag+=c1.imag;
}
Complex add(const Complex &c2,const Complex &c3)
{
    Complex c;
    c.real=c2.real+c3.real;
    c.imag=c2.imag+c3.imag;
    return c;
}
bool is_equal(const Complex &c4,const Complex &c5)
{
    if(c4.real==c5.real&&c4.imag==c5.imag)
        return true;
    else
        return false;
}
double abs(Complex c6)
{
    double a=sqrt((c6.real*c6.real)+(c6.imag*c6.imag));
    return a;
}
int main()
{
    using namespace std;

    Complex c1(-9,5);
    const Complex c2(4);
    Complex c3(c1);

    cout << "c1 = ";
    c1.show();
    cout << endl;

    cout << "c2 = ";
    c2.show();
    cout << endl;
    cout << "c2.imag = " << c2.get_imag() << endl;

    cout << "c3 = ";
    c3.show();
    cout << endl;

    cout << "abs(c1) = ";
    cout << abs(c1) << endl;

    cout << boolalpha;
    cout << "c1 == c3 : " << is_equal(c1, c3) << endl;
    cout << "c1 == c2 : " << is_equal(c1, c2) << endl;

    Complex c4;
    c4 = add(c1, c2);
    cout << "c4 = c1 + c2 = ";
    c4.show();
    cout << endl;

    c1.add(c2);
    cout << "c1 += c2, " << "c1 = ";
    c1.show();
    cout << endl;
}

 

#include <iostream>
#include <string>
using namespace std;
class User
{
public:
    User(string na="Mary",string p="111111",string e="")
    {
        n++;
        name=na;
        passwd=p;
        email=e;
    }
    User()
    {
        n++;
        name="John";
        passwd="112233";
        email="xyz@gmail.com";
    }
    void set_email();
    void change_passwd();
    void print_info();
    static void print_n()
    {
        cout<<"there are "<<n<<" users."<<endl;
    }
private:
    string name;
    string passwd;
    string email;
    static int n;
};
int User::n=0;
void User::set_email()
{
    string w;
    cout<<"Enter email address:";
    cin>>w;email=w;
    cout<<"email is set successfully"<<endl;
}
void User::change_passwd()
{
    string p1,p2,p3,p4,p5;
    cout<<"Enter old password: ";
    cin>>p1;
    if(p1==passwd) 
    {
        cout<<"Enter new password: ";
        cin>>p2;
    }
    else
    {
        cout<<"password input error. Please re-enter again: ";
        cin>>p2;
        if(p2==passwd) 
        {
            cout<<"Enter new password: ";
            cin>>p3;
        }
        else
            cout<<"password input error. Please re-enter again: ";
            cin>>p3;
            if(p3==passwd) 
            {
                cout<<"Enter new password: ";
                cin>>p4;
            }
            else
                cout<<"password input error. Please try after a while."<<endl;
    }    
}
void User::print_info()
{
    cout<<"name: "<<name<<endl;
    cout<<"passwd: "<<"******"<<endl;
    cout<<"email: "<<email<<endl;
}
int main()
{
    using namespace std;

    cout << "testing 1......" << endl;
    User user1("Jonny", "92197", "xyz@hotmail.com");
    user1.print_info();

    cout << endl
         << "testing 2......" << endl
         << endl;
    User user2("Leonard");
    user2.change_passwd();
    user2.set_email();
    user2.print_info();

    User::print_n();
}