实验二 类与对象（二）

实验二任务四

代码：

Complex.hpp:

#pragma once
#include<iostream>
#include"math.h"
using namespace std;

class Complex{
    public:
        Complex(double r = 0.0,double i = 0.0):real{r},imag{i} {}
        Complex(const Complex &c):real{c.real},imag{c.imag} {}
        ~Complex()=default;
        
        double get_real() const {return real;} 
        double get_imag() const {return imag;}
        void add(const Complex &c);
        void show() const;
        
        friend Complex add(const Complex &c1,const Complex &c2);
        friend bool is_equal(const Complex &c1,const Complex &c2);
        friend double abs(Complex &c);
    private:
        double real,imag; 
};
void Complex::show() const{
    if(real==0 && imag==0 )
        cout << 0;
    else if(real!=0 && imag==0)
        cout << real;
    else if(real==0 && imag!=0)
        cout << imag << "i";
    else if(real!=0 && imag>0)
        cout << real << "+" << imag << "i";
    else
        cout << real << imag << "i";        
}

void Complex::add(const Complex &c){
    real+=c.real; imag+=c.imag;
}

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

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

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

task4:

#include "Complex.hpp"
#include <iostream>
void test() {
    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;
}

int main() {
    test();
}

运行结果截图：

实验二任务五

代码：

User.hpp

#pragma once
#include<iostream>
#include<string> 
#include<cstring>
using namespace std;

class User{
    public:
        User(string na,string p="111111",string e=""):name{na},passwd{p},email{e} {n++;}
        void set_email();
        void change_passwd();
        void print_info() const;
        void static print_n() {cout << "there are " << n << " users" << endl;}
    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()
{
    int i;
    string old_passwd=passwd;
    cout << "Enter old password: ";
    for(i = 1;i <= 3;i++)
    {
        cin >> passwd;
        if(passwd==old_passwd)
        {
            cout << "Enter new passwd: ";
            cin >> passwd;
            cout << "new passwd is set successfully..." << endl;
            break;
        }
        else if(passwd!=old_passwd && i<3)
            cout << "password input error. Please re-enter again: ";
        else
            cout << "password input error. Please try after awhile" << endl;
    }
}

void User::print_info() const
{    
    string s2(passwd.length(), '*');
    cout << "name:   " << name << endl;
    cout << "passwd: " << s2 << endl;
    cout << "email:  " << email << endl;
}

task5:

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

void test() {
    using std::cout;
    using std::endl;

    cout << "testing 1......\n";
    User user1("Jonny", "92197", "[email protected]");
    user1.print_info();

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

    cout << endl;
    User::print_n();
}

int main() {
    test();
}

运行结果截图：

test1：

test2：