实验1 类与对象

实验任务三

Complex.hpp

#include<iostream>
#include<cmath>
using namespace std;
class Complex{
    private:
        double real, imag;
    public:
        Complex(double r = 0, double i = 0):real(r), imag(i){}
        Complex(const Complex & c){real = c.real; imag = c.imag;}
        double get_real()const{return real;}
        double get_imag()const{return imag;}
        void show()const;
        void add(const Complex &c);
        friend Complex add(const Complex &c1, const Complex &c2);
        friend bool is_equal(const Complex &c1, const Complex &c2);
        friend double abs(const Complex &c);
}; 

void Complex::show()const{
    if(imag > 0)
        cout << real << " + " <<imag << "i";
    else if(imag < 0)
        cout << real <<" - " << -1*imag << "i";
    else
        cout << real;
}
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;
    return false;
}
double abs(const Complex &c){
    double s = sqrt(c.real * c.real + c.imag * c.imag);
    return s;
}

task3.cpp

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

int main()
{
    using namespace std;

    Complex c1(-9, 2);
    const Complex c2(6.3);
    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;
}

实验结果

实验任务4

User.hpp

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

class User{
    private:
        string name;
        string passwd;
        string email;
        static int n;
    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()const;
        static void print_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(){
    string p;
    cout << "Enter old password: ";
    for(int i=0; i<3; i++){
        cin >> p;
        if(p==passwd){
            cout << "Enter new password: ";
            cin >> passwd;
            cout << "new password is set successfully..." << endl;
            break;
        }
        else{
            cout << "password input error.";
            if(i==0||i==1)
                cout << " Please re-enter again: ";
            else
                cout << "Please try after a while." << endl;
        }
    }    
}

void User::print_info()const{
    cout << "name: " << name << endl;
    cout << "password: ******" << endl;
    cout << "email: " << email << endl;
    
}

void User::print_n(){
    if(n == 1)
        cout << "there is " << n << " user." << endl;
    else
        cout << "there are " << n << " users." << endl;
}

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();
}

实验结果