实验1

设计一个复数类

#ifndef Complex_HPP
#define Complex_HPP

#include<iostream>
#include<cmath>
using namespace std;
class Complex{
private:
    double real;
    double imag;
public:
    Complex() { real = 0; imag = 0; }
    Complex(double i, double j=0) :real{ i }, imag{ j }{real = i; imag = j; }
    Complex(const Complex& c);
    ~Complex() = default;
    double get_real()const;
    double get_imag()const;
    void show();
    Complex add(Complex &c);
    friend bool is_equal(Complex& c1, Complex& c2);//bool类型
    friend int abs(Complex &c);//取模，数学函数sqrt（），数据类型的转换
};
Complex::Complex(const Complex& c)//复制构造函数的定义
{
    real = c.real;
    imag = c.imag;
}
double Complex::get_real()const
{
    return real;
}
double Complex::get_imag()const
{
    return imag;
}
void Complex::show()
{
    if(imag>0||imag==0)
      cout << real << "+" << imag << "i" << endl;//虚部正负的表示：3+4i与3-4i；
    else
    {
        cout << real << imag << "i"<< endl;
    }
}
Complex Complex::add(Complex& c)//有点问题
{
    Complex c0;
    c0.real=real + c.real;
    c0.imag=imag + c.imag;
    return c0;
}
bool is_equal(Complex& c1, Complex& c2)
{
    if (c1.imag == c2.imag && c1.real == c2.real)
    {
        return true;
    }
    else
    {
        return false;
    }
}
int abs(Complex &c)
{
    double x, y;
    x = c.real;
    y = c.imag;
    return static_cast<int>(sqrt(x * x + y * y));
}
#endif 



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

int main()
{
    using namespace std;
    Complex c1(3, -4);
    Complex c2(4.5);//??为什么要加const？？
    Complex c3(c1);

    cout << "c1=";
    c1.show();

    cout << "c2=";
    c2.show();
    cout << "c2.imag=" << c2.get_imag() << endl;

    cout << "c3=";
    c3.show();

    cout << "abs(c1) =";
    cout << abs(c1) << endl;//abs()要写参数表？？

    cout << boolalpha;
    cout << "c1==c3:" << is_equal(c1, c3) << endl;
    cout << "c1==c2:" << is_equal(c1, c2) << endl;

    Complex c4;
    c4 = c1.add(c2);//c4 = add1(c1, c2);
    cout << "c4=c1+c2=";
    c4.show();
    
    c1.add(c2);
    cout << "c1+=c2," << "c1=";
    c1.show();
}

 

设计一个用户类

#ifndef USER_HPP
#define USER_HPP

#include<iostream>
#include<string>
#include<iomanip>

using namespace std;
class User {
private:
    string name;
    string password;
    string s;
    static int count;
public:
    User(string name0, string password0 = "111111", string s0 = "  ") :name{ name0 },password { password0 }, s{ s0 }
    {
        name = name0;
        password = password0;
        s = s0;
        ++count;
    }
    ~User() = default;
    void set_email();
    void change_passwd();
    void print_info()const;
    void print_n() { cout << "there are:" << count << endl<<"users."; }
};
int User::count = 0;

void User::set_email()
{
    cout << "Please enter email address:";
    cin >> s;
    cout << endl;
    cout << "email is set successfully！"<<endl;

}
void User::change_passwd()
{
    string a,b;
    int i;
    cout << "Please enter old password:";
    cin >> a;
    if(a==password)
    {
        cout << "Please enter new password:";
        cin >> b;
        if(a!=b)//不能使用 strcmp(a, b);strcmp(const char *str1,const char *str2);
        {
           cout << "new passwd is set successfully！"<<endl;

        }
    }
    else
    {
        for (i = 1; i < 3; i++)
        {
            cout << "Error,please enter old password again:";
            cin >> a;
        }
        cout << "please try it after!" << endl;
    }
    
}
void User::print_info()const
{
    cout << "name:" << name << endl;
    cout << "passwd:" << "******" << endl;
    cout << "email:" << s << endl;
}

#endif



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

int main()
{
    using namespace std;

    cout << "testing 1……" << endl;
    //User user1("Jonny","92197", "xyz@hotmail.com");
    User user1("Jonny", "92197", "xyz@hotmail.com");
    user1.print_info();

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

}

 总结：

设计一个复数类实验：1.复数的虚部的表示（>0,<0)

2.add（）如何实现：两个复数相加得到一个新的复数、把一个复数加给自身

3.取模

4.friend友元函数的使用

设计一个复数类用户类实验：1.string(char  a[]？）

2.static