实验一 类与对象

1、实验任务1-2

略

2、试验任务3

实验流程: 不使用C++标准库，自行设计并实现一个复数类Complex，使用task3.cpp中的代码，测试类Complex的各项接口是否正确。

 

task3.cpp 

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

int main()
{
    using namespace std;

    Complex c1(12, -12);
    const Complex c2(123);
    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;
}

 

 Complex.cpp

#ifndef COMPLEX_HPP
#define COMPLEX_HPP

#include<iostream>
#include<cstring>
#include<cmath>
using namespace std;

//Complex类的定义
class Complex{
    
    friend Complex add(const Complex& a,const Complex& b);
    friend bool is_equal(const Complex& a,const Complex& b);
    friend double abs(const Complex& a);
    
    public:
        Complex(double a=0,double b=0):real(a),imag(b){}
        
        Complex(const Complex& p):real(p.get_real()),imag(p.get_imag()){}
        
        double get_real() const{
            return real;
        }
        
        double get_imag() const{
            return imag;
        }
        
        void show() const{
            cout<<real;
            if(imag!=0)    cout<<(imag<0?" - ":" + ")<<abs(imag)<<"i";
            cout<<endl;
        }
        
        void add(const Complex& a){
            this->real+=a.get_real();
            this->imag+=a.get_imag();
        }
        
    private:
        double real;
        double imag;
};

Complex add(const Complex& a,const Complex& b){
    double m_real=a.real+b.real;
    double m_imag=a.imag+b.imag;
    return Complex(m_real,m_imag);
}
    
bool is_equal(const Complex& a,const Complex& b){
    if(a.real==b.real&&a.imag==b.imag) return true;
    else return false;
}

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

#endif

 

输出结果如下:

 

 

 

 3、试验任务4

实验流程：设计并实现一个用户类User，并在主函数中使用和测试这个类。

 

task4.cpp

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

int main()
{
    using namespace std;

    cout << "testing 1......" << endl;
    User user1("GGG", "12345", "abc@abc.com");
    user1.print_info();

    cout << endl
         << "testing 2......" << endl
         << endl;
    User user2("AAA");
    user2.change_passwd();
    user2.set_email();
    user2.print_info();
    
    User::print_n();
    
    cout << endl
         << "testing 3......" << endl
         << endl;
    user2.change_passwd();
}

 

User.hpp

#ifndef USER_HPP
#define USER_HPP


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

//User类的定义 
class User{
    public:
        User(string m_name,string m_passwd="111111",string m_email=""):name(m_name),passwd(m_passwd),email(m_email){n++;}
        
        static void print_n(){
            cout<<"there are "<<n<<" users"<<endl;
        }
        
        void set_email() {
            cout<<"Enter email address:";
            string m_email;
            cin>>m_email;
            email = m_email;
            cout<<"email is set successfully..."<<endl;
        }
        
        void change_passwd(){
            string m_passwd;
            cout<<"Enter old passwd:";
            cin>>m_passwd;
            if(m_passwd==passwd){
                set_passwd();
                return;
            }
            cout<<"passwd input error.";
            int cnt=0;
            while(cnt<2){
                cout<<"Please re-enter again:";
                cin>>m_passwd;
                if(m_passwd==passwd){
                    set_passwd();
                    return;
                }
                cout<<"passwd input error.";
                cnt++;
            }
            cout<<"Please try after a while."<<endl;
        }
        
        void print_info(){
            cout<<"email:\t"<<name<<endl;
            cout<<"passwd:\t******"<<endl;
            cout<<"email:\t"<<email<<endl;
        }
        
    private:
        string name,passwd,email;
        static int n;
        void set_passwd(){
            string new_passwd;
            cout<<"Enter new passwd:";
            cin>>new_passwd;
            passwd=new_passwd;
            cout<<"new passwd is set successfully..."<<endl;
        }
};

int User::n=0;

#endif

 

输出结果如下: