/* Why is Encapsulation so importand in OOP? Here is my Answer. */ #include #include using namespace std; class user { protected: string name; string password; int trys; public: user (string n, string pw) { name = n; password = pw; trys = 0; cout << "New User '" << name << "' with Password '" << password << "' created.\n"; cout << name << " has " << 3 - trys << " Chances to input the correct Password.\n"; } string get_name() { return name; } bool test_pw (string pw) { if (trys >= 3) { cout << "Wrong Passwort for to many Times. Please contact the Administrator.\n"; return false; } if (pw == password) { trys = 0; return true; } else { trys += 1; cout << "Wrong Passwort! " << 3 - trys << " Tryes left.\n"; return false; } } }; class secret { protected: string top_secret; class user *owner; public: secret (class user *n) { top_secret = "Top secred encapsulated Information"; owner = n; cout << "New Message created. The owner is " << owner->get_name() << ".\n"; cout << "Standard Message is '" << top_secret << "'.\n"; } void get_secret (string n, string pw) { if (owner->get_name() == n && owner->test_pw(pw) == 1) { cout << top_secret; } else {cout << "Access denied!";} } void set_secret (string new_secret, string n, string pw) { if (owner->get_name() == n && owner->test_pw(pw) == 1) { top_secret = new_secret; cout << "Top Secret Information has been changed!"; } else {cout << "Access denied!";} } }; int main() { cout << "OK, let's start and create a new User with the Constructor of the Class 'user':\n\n"; cout << "*****\n"; cout << "user Dude ('Dude', 'Lebowsky'); ...\n"; user Dude ("Dude", "Lebowsky"); cout << "*****\n\n"; cout << "All Conditions of the User are protected. "; cout << "To call 'dude.name' would lead to an Error 'declared protected here'. "; cout << "To see the Name of the User there is a public Funcition 'get_name()':\n\n"; cout << "*****\n"; cout << "cout << Dude.get_name(); ... \n"; cout << Dude.get_name() << "\n"; cout << "*****\n\n"; cout << "To ask for 'dude.password' would cause an Error, too. But there is also no Function that returns the Password. "; cout << "So we can just test, if a Password is true (1) or false (0) using the public Function 'test_pw()'.\n\n"; cout << "*****\n"; cout << "cout << Dude.test_pw(Lebowsky) ...\n"; cout << Dude.test_pw("Lebowsky") << "\n"; cout << "*****\n\n"; cout << "Be carefull, because the Number of Tests is limited!\n\n"; cout << "*****\n"; cout << "cout << Dude.test_pw(lebowski) ...\n"; cout << Dude.test_pw("lebowski") << "\n"; cout << "*****\n\n"; cout << "Now let's create a new Top Secret Information with the Constructor Function of the Class 'secret'.\n\n"; cout << "*****\n"; cout << "secret Dudes_Secret(&Dude); ...\n"; secret Dudes_Secret(&Dude); cout << "\n*****\n\n"; cout << "The Secret gets a Pointer (&Dude) to the Users Memory Adress as Argument. So the Secret is personalized and has access to all public Functions of the User Dude. "; cout << "Now we can set a new Message using the 'set_secret()' Function with the new Message and the Passwort as Arguments:\n\n"; cout << "*****\n"; cout << "Dudes_Secret.set_secret('Dudes personal Secret', 'Dude', lebowski') ...\n"; Dudes_Secret.set_secret("Dudes personal Secret", "Dude", "lebowski"); cout << "\n*****\n\n"; cout << "Uuups, that was the wrong Password. Take Care and try it again.\n\n"; cout << "*****\n"; cout << "Dudes_Secret.set_secret('Dudes personal Secret', 'Tude', Lebowsky') ...\n"; Dudes_Secret.set_secret("Dudes personal Secret", "Tude", "Lebowsky"); cout << "\n*****\n\n"; cout << "Grrr, now the Password was correct, but not the Username!\n\n"; cout << "*****\n"; cout << "Dudes_Secret.set_secret('Dudes personal Secret', 'Dude', Lebowsky') ...\n"; Dudes_Secret.set_secret("I like White Russian!!!", "Dude", "Lebowsky"); cout << "\n*****\n\n"; cout << "There is also a Function 'get_secret()' within the secret Class."; cout << "This Function allows us to read the Secret - but only with the correct Username and Password.\n\n"; cout << "*****\n"; cout << "Dudes_Secret.get_secret('Dude', 'Lebowsky') ...\n"; Dudes_Secret.get_secret("Dude", "Lebowsky"); cout << "\n*****"; return 0; }

OOP Passwort encapsulation