实验一类与对象

#include <iostream>

#include <cmath>
using namespace std;

class Complex{
private:
double real;
double imag;
public:
Complex(double a=0,double b=0):real(a),imag(b){}
Complex(const Complex &m){
real=m.real;
imag=m.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 &c1);
};
void Complex::show() const
{
if(real==0)
{
if(imag!=0)
cout<<imag<<"i";
else
cout<<"0";
}
else
{
if(imag==0)
cout<<real;
if(imag>0)
cout<<real<<"+"<<imag<<"i";
if(imag<0)
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 c3;
c3.real=c2.real+c1.real;
c3.imag=c2.imag+c1.imag;
return c3;
}
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(const Complex &c)
{
return sqrt(c.real*c.real+c.imag*c.imag);
}

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

int main()
{
    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;
}

 

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

class User {
private:
string name;
string passwd;
string email;
static int n;
public:
User(string nam, string pass = "111111", string emai = "") :name (nam) ,passwd(pass), email(emai)
{
n++;
}
void set_email()
{
cout << "Enter email address: ";
cin >> email;
}
void change_passwd()
{
string text;
int i = 0;
cout << "Enter old password: ";
cin >> text;
while (i<=3) {
if ( text == passwd ) {
cout << "Enter new passwd: ";
cin >> text;
cout << "new passwd is set successfully..." << endl;
passwd = text;
break;
}
else {
i++;
if ( i == 3 ) {
cout << "password input error. Please try after a while." << endl;
break;
}
cout << "password input error. Please re-enter again: ";
cin >> text;
}
}
}
void print_info()
{
cout << "name:   " << name << endl;
cout << "passwd: ******" << endl;
cout << "email:  " << email << endl;
}
static void print_n()
{
cout << "there are " << n << " users." << endl;
}
};
int User::n = 0;

#include "User2.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();
}