#ifndef COMPLEX_HPP
#define COMPLEX_HPP

#include<iostream>
#include<cmath>

using namespace std;

class Complex {
    private:
        double real;
        double imag;
    public:
        Complex();
        Complex(double real0);
        Complex(double real0,double imag0);
        Complex(const Complex &obj);

        double get_real()const;
        double get_imag()const;
        void show()const;
        void add(const Complex &obj);

        friend Complex add(Complex obj1,Complex obj2);
        friend bool is_equal(const Complex &obj1,const Complex &obj2);
        friend double abs(const Complex &obj);
};

Complex::Complex() {
    real=imag=0;
}
Complex::Complex(double real0) {
    real=real0;
    imag=0;
}
Complex::Complex(double real0,double imag0) {
    real=real0;
    imag=imag0;
}
Complex::Complex(const Complex &obj) {
    real=obj.real;
    imag=obj.imag;
}

double Complex::get_real()const {
    return real;
}
double Complex::get_imag()const {
    return imag;
}
void Complex::show()const {
    if(imag!=0)
        cout<<real<<imag<<"i";
    else
        cout<<real;
}
void Complex::add(const Complex &obj) {
    real=real+obj.real;
    imag=imag+obj.imag;
}

Complex add(Complex obj1,Complex obj2) {
    obj1.real=obj1.real+obj2.real;
   obj1.imag=obj1.imag+obj2.imag;
   return obj1;
}
bool is_equal(const Complex &obj1,const Complex &obj2) {
    if(obj1.real==obj2.real&&obj1.imag==obj2.imag) return true;
    else return false;
}
double abs(const Complex &obj) {
    return sqrt(pow(obj.real,2)+pow(obj.imag,2));
}

 

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;
}

 

 

 

#ifndef USER_HPP
#define USER_HPP

#include<iostream>
#include<string>

using namespace std;

class User
{
    public:
        User(string name0,string passwd0="111111",string email0=""):name(name0),passwd(passwd0),email(email0){n++;}
        void set_email();
        void change_passwd();
        void print_info();
        static void print_n();
        ~User(){}
    private:
        string name,passwd,email;
        static int n;
};

int User::n=0;

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

void User::change_passwd() 
{
    string oldpasswd;
    int j=0;
    cout<<"Enter old password: ";
    cin>>oldpasswd;
    
    if (oldpasswd == passwd)
    {
        cout << "Enter new passwd: ";
        cin >> passwd;
    }
        
    else
    {
        
        do
        {
            j++;
            cout<<"password input error. Please re-enter again: "; 
            cin>>oldpasswd;
            if(j==2)
            {
                cout<<"password input error. Please try after a while."<<endl;
                break; 
            }
        }while(oldpasswd!=passwd);
        if(oldpasswd==passwd)
        cin>>passwd;
    }
}

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

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

 

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();
}