test2

#pragma once
#include<iostream>
#include <cmath>
using std::cout;
using std::endl;

class Complex
{
public:
    Complex(double r = 0, double i = 0):real(r),imag(i){};
    Complex(const Complex& r):real(r.real),imag{r.imag}{};
    double get_real() const{ return real; };
    double get_imag() const{ return imag; };
    void add(const Complex& r) { real += r.real; imag += r.imag; };
    void show() const;
    friend Complex add(const Complex& r1,const Complex& r2);
    friend bool is_equal(const Complex& r1,const  Complex& r2);
    friend double abs(const Complex& r1);
private:
    double real, imag;
    
};
void Complex::show()const {
    cout << real;
    if (imag > 0)cout << "+" << imag << "i"<<endl;
    else if(imag<0)cout << imag <<"i"<< endl;
}
 Complex add(const Complex &r1,const Complex &r2)
 {
         Complex r3;
         r3.real = r1.real + r2.real;
         r3.imag = r1.imag + r2.imag;
         return r3;
 }
 bool is_equal(const Complex& r1, const  Complex& r2) {
     if (r1.real == r2.real && r1.imag == r2.imag)
         return true;
     else 
         return false;
 }
 double abs(const Complex& r1) {
     double x;
         x= sqrt(r1.real * r1.real + r1.imag * r1.imag);
     return x;
 }

修改后：

#pragma once
#include<iostream>
#include<string>
using std::string;
using std::cout;
using std::endl;
using std::cin;
class User
{
public:
User(string n, string p = "111111" , string e = "") :
name{ n }, password{ p }, email{ e } {total++;};
void set_email();
void change_passwd();
void print_info();
void static print_n();
static int total;
private:
string name;
string password;
string email;
};
int User::total = 0;
void User::set_email()
{
cout << "Enter email address:";
cin >> email;
cout << endl << "email is set successfully";
}
void User::change_passwd()
{
int x = 0;
cout << "Enter old password:";
cin >> password;
x++;
while (password != "111111" && x < 3)
{
cout << "password input error.please re-enter again:";
cin >> password;
cout << endl;
x++;
}
if (x < 3)
{
cout << "Enter new passd:";
cin >> password;
cout << endl;
cout << "new passwd is set sucessfully..." << endl;
}

else
{
password = "111111";
cout << "password input error.please try after a while." << endl;
}
}
void User::print_info()
{
int m = size(password);
cout << "name:" << name << endl;
cout << "passwd:";
for (int i = 0; i < m; i++)
{
cout << "*";
}
cout << endl;
cout << "email:" << email << endl;
}
void User::print_n()
{
cout << "there are" << total << "users";
}