【實驗一】類與物件
阿新 • • 發佈：2021-10-21
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目錄1、任務一
不使用C++標準庫，自行設計並實現一個複數類Complex，使其滿足如下要求：
- 資料成員
用來表示複數的實部real和虛部imag，實部、虛部，均為小數形式。 - 函式成員
- 建構函式
支援以下方式定義複數物件：Complex c1; // 不帶引數 Complex c2(3); // 只有一個引數，相當於3 + 0i Complex c3(3, 4); // 兩個引數，相當於3 + 4i Complex c4(c3); // 用c3構造c4 - 成員函式
- get_real() 返回複數實部
- get_imag() 返回複數虛部
- show() 用於輸出複數。要求以 3 + 4i ， 3 - 4i 這樣的形式輸出
- add() 用於把一個複數加到自身，比如 c1.add(c2) ，相當於 c1 += c2
- 建構函式
- 友元函式
- add() 用於實現兩個複數相加，返回複數。比如 c3 = add(c1, c2);
- is_equal() 用於判斷兩個複數是否相等，返回true/false。比如 is_equal(c1, c2)
- abs() 用於對複數進行取模運算
將類Complex的定義及友元函式實現，單獨儲存在檔案Complex.hpp中。
使用ComplexTest.cpp中的程式碼，測試類Complex的各項介面是否正確。
Complex.hpp
#include <iostream> #include <cmath> class Complex { private: double a; double b; public: Complex(); Complex(double a); Complex(double a, double b); Complex(const Complex &complex_temp); ~Complex(); double get_real() const; double get_imag() const; void show() const ; void add(Complex complex_temp); Complex add(const Complex complex_temp) const; bool equal(const Complex complex_temp) const; double abs(const Complex complex1) const; friend Complex add(const Complex complex1, const Complex complex2); friend bool is_equal(const Complex complex1, const Complex complex2); friend double abs(const Complex complex_temp); }; Complex::Complex() { } Complex::Complex(double a) : a{a} { } Complex::Complex(double a, double b) : a{a}, b{b} { } Complex::Complex(const Complex &complex_temp) : a{complex_temp.a}, b{complex_temp.b} { } Complex::~Complex() { } double Complex::get_real() const { return a; } double Complex::get_imag() const { return b; } void Complex::show() const { std::cout << a << " + " << b << "i"; } void Complex::add(Complex complex_temp) { a += complex_temp.a; b += complex_temp.b; } Complex Complex::add(const Complex complex_temp) const { return Complex(a + complex_temp.get_real(), b + complex_temp.get_imag()); } bool Complex::equal(const Complex complex_temp) const { if(a == complex_temp.get_real() && b == complex_temp.get_imag()){ return true; } return false; } double Complex::abs(const Complex complex_temp) const { return sqrt(pow(complex_temp.get_imag(), 2) + pow(complex_temp.get_real(), 2)); } Complex add(const Complex complex1, const Complex complex2); bool is_equal(const Complex complex1, const Complex complex2); double abs(const Complex complex_temp); Complex add(const Complex complex1, const Complex complex2){ complex1.add(complex2); return complex1; } bool is_equal(const Complex complex1, const Complex complex2){ return complex1.equal(complex2); } double abs(const Complex complex_temp){ return(complex_temp.abs(complex_temp)); }
ComplexTest.cpp
#include "Complex.hpp" #include <iostream> #include <cmath> using namespace std; int main(){ using namespace std; Complex c1(5, -4); const Complex c2(5.5); 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; system("pause"); return 0; }
執行結果：
2、任務二
設計並實現一個使用者類User，並在主函式中使用和測試這個類。具體要求如下：
- 資料成員
每個使用者有使用者名稱(name)、密碼(passwd)、聯絡郵箱(email)三個屬性。
還有一個類屬性，用於記錄使用者總數n。 - 函式成員
- 建構函式
如果定義使用者物件時未設定密碼和郵箱，密碼預設為6個1，聯絡郵箱預設為空串。User u1("Mary"); // 密碼和郵箱，使用預設設定 User u2("John", "112233", "[email protected]")- 成員函式
- set_email()
設定郵箱。提示使用者從鍵盤輸入郵箱。 - change_passwd()
修改密碼。修改密碼前，要求先輸入舊的密碼，驗證無誤後，才允許修改；如果輸入舊
密碼時，連續三次輸入錯誤，則提示使用者稍後再試，暫時退出修改密碼程式。 - print_info()
列印使用者名稱、密碼、聯絡郵箱。其中，密碼以6個*方式顯示。
- set_email()
User類的定義和實現，儲存在檔案User.hpp中:
#include <iostream>
#include <string>
using namespace std;
class User
{
private:
string name;
string passwd;
string email;
static int count;
public:
User();
User(string name);
User(string name, string passwd, string email);
~User();
static void print_count();
void set_email();
void change_passwd();
void print_info();
};
int User::count = 0;
void User::print_count(){
cout << "\nthere are " << count << "users\n";
}
User::User()
{
this->name = "無";
this->passwd = "666666";
this->email = "[email protected]";
this->count++;
}
User::User(string name) : name{name}
{
this->passwd = "666666";
this->email = "[email protected]";
this->count++;
}
User::User(string name, string passwd, string email) : name{name}, passwd{passwd}, email{email}
{
this->count++;
}
User::~User()
{
this->count++;
}
void User::set_email()
{
string email_temp;
string passwd_temp;
cout << "\nDear " << name << "~" << "\nCheck password: ";
cin >> passwd_temp;
while (passwd_temp != passwd)
{
cout << "password input error. Please re-enter again: ";
cin >> passwd_temp;
}
cout << "Enter email address: ";
cin >> email_temp;
this->email = email_temp;
cout << "email is set successfully...\n";
}
void User::change_passwd()
{
string passwd_temp;
cout << "\nDear " << name << "~" << "\nEnter old password: ";
cin >> passwd_temp;
while (passwd_temp != passwd)
{
cout << "password input error. Please re-enter again: ";
cin >> passwd_temp;
}
cout << "Enter new passwd: ";
cin >> passwd_temp;
this->passwd = passwd_temp;
cout << "passwd changed successfully\n";
}
void User::print_info()
{
cout << "\n使用者名稱:" << name << "\n密碼:******" << "\n郵箱:" << email << endl;
}
User類的使用和測試，儲存在檔案UserTest.cpp中:
#include "Complex.hpp"
#include <iostream>
#include <cmath>
using namespace std;
int main(){
using namespace std;
Complex c1(5, -4);
const Complex c2(5.5);
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;
system("pause");
return 0;
}
執行結果：
實驗總結
const的用法，以及建構函式、初始化列表、友元函式。
加深對面向物件中封裝的理解