实验一

Task3: Complex.hpp

#include<iostream>
#include<cmath>
using namespace std;
class Complex
{
    public:
        Complex(double m_real=0,double m_imag=0):real(m_real),imag(m_imag){
        }
        Complex(const Complex &c){
            real = c.real;
            imag = c.imag;
        }
        double get_real() const;//成员函数 
        double get_imag() const;
        void show() const;
        void add(const Complex &obj)
        {
            real+=obj.real;
            imag+=obj.imag;
        }
        friend double abs(const Complex &c1);//友元函数 
        friend bool is_equal( const Complex &c1, const Complex &c2);
        friend Complex add(const Complex &c1, const Complex &c2);
        ~Complex()=default;
        
    private:
        double real,imag;
        
};

double Complex::get_real() const{
    return real;
}

double Complex::get_imag() const{
    return imag;
}

void Complex::show() const{
    if(real!=0){
        if(imag){//判断imag是否为零 
            if(imag>0)
                cout << real << "+" << imag << "i";
            else{
                cout << real << imag << "i";
            }
        }
        else
                cout << real;
    }
    else{
        if(imag){//判断imag是否为零 
            if(imag>0)
                cout << real << "+" << imag << "i";
            else{
                cout << real << imag << "i";
            }
        }
        else
                cout << real;
    }
}

Complex add(const Complex &c1, const Complex &c2){
    Complex c3;
    c3.real = c1.real + c2.real;
    c3.imag = c1.imag + c2.imag;
    return c3;
}

double abs(const Complex &c1){
    return sqrt(c1.real*c1.real+c1.imag*c1.imag);
}

bool is_equal(const Complex &c1,const Complex &c2){
    if(c1.real==c2.real&&c1.imag==c2.imag)
        return true;
    else 
        return false;
}

task3.cpp

#include "Complex.hpp"
#include <iostream>

int main()
{
    using namespace std;

    Complex c1(3, -4);
    const Complex c2(4.5);
    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;
}

 task4: User.hpp

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

class User{
    private:
        string m_name,m_password,m_email;
        static int n; 
    public:
        User(){    n++; }
        User(string name,string password = "111111",string email = "")
            :m_name(name),m_password(password),m_email(email){n++;} 
        void set_email() ;
        void change_passwd() ;
        void print_info() ;
        static void print_n();
};
int User::n = 0;

void User::print_n(){
    cout << "there are " << n << " users." << endl;
}

void User::set_email(){
    cout << "Enter email address: " << endl ;
    cin >> m_email ;
    cout << "email is set successfully...";
} 

void User::change_passwd() {
    cout << "Enter old password: ";
    string t1;
    int num=0;
    string &t2 = m_password;//引用，给成员密码取别名 
    cin >> t1;
    for(int i=0;i<3;i++){
        if(t1 == m_password){
            cout << "Enter new passwd: ";
            cin >> t2 ;
            cout << "new passwd is set successfully..." << endl;
            return ;
        }
        else if(i!=2){
            cout << "password input error. Please re-enter again: ";
            cin >> t1 ;
        }
        else{
            cout << "password input error. Please try after a while. " << endl;
            return;
        }
    }
}

void User::print_info() {
    cout << "name: " << m_name << endl;
    cout << "passwd: ******" << endl;
    cout << "email: " << m_email << endl;
}

task4.cpp

#include "User.hpp"
#include <iostream>

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();
}