Complex.hpp

#ifndef COMPLEX_HPP
#define COMPLEX_HPP

#include <iostream>
#include <cmath>
#include <iomanip>

class Complex {
public:
    Complex(double real0 = 0, double imag0 = 0) :real(real0), imag(imag0) {
    }
    ~Complex() = default;
    Complex(const Complex& p);
    double get_real()const;
    double get_imag()const;
    void show()const;
    void add(Complex c);
    friend Complex add(Complex c1, Complex c2);
    friend bool is_equal(Complex c1, Complex c2);
    friend double abs(Complex c);
private:
    double real;
    double imag;
};

Complex::Complex(const Complex& p) :real(p.real), imag(p.imag) {
}
double Complex::get_real()const{ return real; }
double Complex::get_imag()const{ return imag; }
void Complex::show()const {
    if(imag>0)
        std::cout << real << " +" << imag << "i" ;
    else if(imag<0)
        std::cout << real << " "<< imag << "i" ;
    else
        std::cout << real ;
}
void Complex::add(Complex c) {
    real = real + c.real;
    imag = imag + c.imag;
}
Complex add(Complex c1, Complex c2) {
    Complex c3;
    c3.real = c1.real + c2.real;
    c3.imag = c1.imag + c2.imag;
    return c3;
}
bool is_equal(Complex c1, Complex c2) {
    if (c1.real == c2.real && c1.imag == c2.imag)
        return true;
    else
        return false;
}
double abs(Complex c) {
    double s;
    s = sqrt(c.real * c.real + c.imag * c.imag);
    return s;
}

#endif

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;
}

User.hpp

#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() {
        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 e;
    cout << "Enter email address: ";
    cin >> e;
    email = e;
    cout << "email is set successfully..." << endl;
}
void User::change_passwd() {
    string p1, p2, p3, p;
    cout << "Enter old passwd: ";
    cin >> p1;
    if (p1 == passwd)
    {
        cout << "Enter new passwd: ";
        cin >> p;
        passwd = p;
        cout << "new passwd is set successfully..." << endl;
    }
    else {
        cout << "psssword input error. Please re-enter again: ";
        cin >> p2;
        if (p2 == passwd)
        {
            cout << "Enter new passwd: ";
            cin >> p;
            passwd = p;
            cout << "new passwd is set successfully..." << endl;
        }
        else {
            cout << "psssword input error. Please re-enter again: ";
            cin >> p3;
            if (p3 == passwd)
            {
                cout << "Enter new passwd: ";
                cin >> p;
                passwd = p;
                cout << "new passwd is set successfully..." << endl;
            }
            else
                cout << "psssword input error. Please try after a while" << endl;
        }
    }
}
void User::print_info() {
    cout << "name:   " << name << endl;
    cout << "passwd: ******" << endl;
    cout << "email:  " << email << 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();
}

 实验总结：

实验一加深了对友元函数及const的理解与运用

实验二是对于string类的简单认识