Design a class named PersonData with the following member variables:
• lastName
• firstName
• address
• city
• state
• zip
• phone
Write the appropriate accessor and mutator functions for these member variables.
Next, design a class named CustomerData , which is derived from the PersonData class.
The CustomerData class should have the following member variables:
• customerNumber - The customerNumber variable will be used to hold a unique integer for each customer.
• mailingList - The mailingList variable should be a bool . It will be set to true if the customer wishes to be on a mailing list, or false if the customer does not wish to be on a mailing list.
The CustomerData class should also maintain a static variable to keep track of the total number of customers created and a static function to access that number.
Write appropriate accessor and mutator functions for these member variables.
Demonstrate an object of the CustomerData class in a simple program.
#include <iostream>
#include <string>
using namespace std;
class PersonData
{
private:
string lastName;
string firstName;
string address;
string city;
string state;
string zip;
string phone;
public:
void setLastName(string newLastName);
void setFirstName(string newFirstName);
void setAddress(string newAddress);
void setCity(string newCity);
void setState(string newState);
void setZip(string newZip);
void setPhone(string newPhone);
string getLastName();
string getFirstName();
string getAddress();
string getCity();
string getState();
string getZip();
string getPhone();
};
void PersonData::setLastName(string newLastName)
{
lastName = newLastName;
}
void PersonData::setFirstName(string newFirstName)
{
firstName = newFirstName;
}
void PersonData::setAddress(string newAddress)
{
address = newAddress;
}
void PersonData::setCity(string newCity)
{
city = newCity;
}
void PersonData::setState(string newState)
{
state = newState;
}
void PersonData::setZip(string newZip)
{
zip = newZip;
}
void PersonData::setFirstName(string newFirstName)
{
firstName = newFirstName;
}
class CustomerData: public PersonData
{
public:
};
int main()
{
system("pause");
return 0;
}
I'm not really sure where to go from here. Any suggestions or tips would be awesome!
You want to derive a class CustomerData. You can add this code for that class
class CustomerData: public PersonData
{
public:
int customerNumber;
bool mailingList;
static int totalCustomer;
};
int CustomerData :: totalCustomer=0; This code is to initialize the static variable of the class.
You can Write the code to get data by using the prototype defined by you.
In main you can use the object of CustomerData class to access the setters and mutator functions defined in the PersonData class.
for example :
CustomerData obj;
obj.setLastName("XYZ");
and to get the last name you can write
obj.getLastName();
but remember you have to write the getLastName() and all get______() functions.
Related
Hello I am fairly new in C++ and I am trying to make a programm that you have objects of Application class.
Application class should inherit from two classes. The class Games and the class desktopApp.
When I build my programm I get the two followin errors:
no matching function for call to 'desktopApp::desktopApp()
no matching function for call to 'Games::Games()
My questions are:
Why I get these errors?
How can I call the constructor of the parent class I want to make an object of everytime?
Do I need to make two constructors one for each parent class in Application class?
Thank you very much.
Games class code:
class Games
{
string category;
float price;
public:
Games (string category, float price)
{
this->category = category;
this->price = price;
}
};
desktopApp class code:
class desktopApp
{
string edition;
vector<string> ratings;
public:
desktopApp (string edition, vector<string> ratings)
{
this->edition = edition;
copy(this->ratings.begin(), this->ratings.end(), back_inserter(ratings));
}
};
Application class code:
class Application:public desktopApp, public Games
{
string name;
public:
Application (string name, string category, float price):Games (category, price)
{
this->name = name;
}
Application (string name, string edition, vector<string> ratings):desktopApp (edition, ratings)
{
this->name = name;
}
};
Main:
int main()
{
Applications game1("aGame", "Violent", 45.7);
}
Having two base classes A and B, a class C that inherits from both, looks like this:
class C : public A, public B{
public:
C(/*params*/) : A(/*params*/), B(/*params*/){/*code*/}
};
So in your case your Application should looks like this:
class Application:public desktopApp, public Games
{
string name;
public:
Application(string edition, vector<string> ratings, string name, string category, float price) :
desktopApp(edition,ratings),
Games(category,price)
{
this->name = name;
}
Application(string category, float price, string name, string edition, vector<string> ratings) :
Games(category,price),
desktopApp(edition,ratings)
{
this->name = name;
}
};
I am doing the Big c++ 2nd edition questions and I am on classes, I am stuck on a question. Basically I have to classes one called "person" and one called "Pemployee", I need to write the member functions of "Pemployee".
They gave me the declarations I need to implement the definitions.
What I don't get how to do is write call name, since it needs to call the private variable "person_data" which is a person object, I cannot access the string name directly but the member function of "person" has a "get_name" function which returns void, I dont understand how to get a string returned if I cannot return from the other definition.
Here are the two classes.
class Person
{
public:
Person();
Person(string pname, int page);
void get_name() const;
void get_age() const; //returns void
private:
string name;
int age; // 0 if unknown
};
class PEmployee
{
public:
PEmployee();
PEmployee(string employee_name, double initial_salary);
void set_salary(double new_salary);
double get_salary() const;
string get_name() const; //assuming I need to call person get_name
private:
Person person_data;
double salary;
};
So once again, how do I call the "Pemployee" get_name to return the string name of the person_data private variable
Typo in the book, Person::get_name should return string
A lot of programming books teach you to add get and set methods to your classes when the variable needs to be read or modified from outside of the class.
You need to create get methods for each of the private variables that your want value access to outside of the class.
You will need a set methods if you want to change the values from outside the class.
Example get method for your class
std::string get_name() const {return this->name;}
These signatures in the class called Person are pointless:
void get_name() const;
void get_age() const;
It is very probable that it is a typo. If it returned string then it whouldn't be pointless.
However if you would not like to change the functions signature or add a new memeber to the Person, then you should declare PEmployee as friend of Person, so member functions of PEmployee can reach private and protected members of Person. You can see below how to do this.
#include <string>
class PEmployee;
class Person
{
public:
friend PEmployee;
Person(){ }
Person(std::string pname, int page);
void get_name() const;
void get_age() const; //returns void
private:
std::string name;
int age; // 0 if unknown
};
class PEmployee
{
public:
PEmployee();
PEmployee(std::string employee_name, double initial_salary);
void set_salary(double new_salary);
double get_salary() const;
std::string get_name() const; //assuming I need to call person get_name
private:
Person person_data;
double salary;
};
Looked at similar threads and this doesn't show up. Basically I want chef to inherit the functions and data from employee (base class) but i'm having issues with the constructor for the derived class. I'm getting the error: no matching function for call to 'Employee::Employee()' Could someone show me how to declare my constructors for this derived class and my future derived classes for this program. Tried a bunch of things and can't seem to get it working.
class Employee
{
public:
Employee(int theempID, string thefirstName, string thelastName, char theempClass, int thesalary)
{
this->empID = theempID;
this->firstName = thefirstName;
this->lastName = thelastName;
this->empClass = theempClass;
this->salary = thesalary;
};
protected:
int empID;
string firstName;
string lastName;
char empClass;
int salary;
};
class Chef : public Employee
{
public:
Chef(int theempID, string thefirstName, string thelastName, char theempClass, int thesalary, string theempCuisine) : Employee() {}
{
this->empID = theempID;
this->firstName = thefirstName;
this->lastName = thelastName;
this->empClass = theempClass;
this->salary = thesalary;
this->empCuisine = theempCuisine;
};
string getCuisine()
{
return empCuisine;
}
protected:
string empCuisine;
};
#endif // EMPLOYEE
Employee() is trying to default construct an Employee but there is no default constructor for Employee. Instead, construct it with the parameters your constructor it expects.
The Chef constructor should look like this:
Chef(int theempID, string thefirstName, string thelastName, char theempClass, int thesalary, string theempCuisine) :
Employee(theempID, thefirstName, thelastName, theempClass, thesalary), empCuisine(theempCuisine)
{}
Note the body of the constructor is empty. The Employee base class and the member variable are initialized in the initialization list. No assignment necessary in the body. You should also change the base class constructor so it uses initialization instead of assignment.
I am new into classes, and I have been trying to create this simple class code but every time I get an error. It works fine when I don't use the access specifier private, but I want to practice how to use private. Could you please tell me what's wrong?
#include <iostream>
#include <string>
using namespace std;
class Student
{
private:
string name;
int ID;
public:
void setName(string);
string getName();
void setID(int);
int getID();
};
void Student::setName(string n)
{
name=n;
}
string Student::getName()
{
cout<<name;
return name;
}
void Student::setID(int i)
{
ID=i;
}
int Student::getID()
{
cout<<ID;
return ID;
}
int main ()
{
Student S;
cout<<"Enter Student name: ";
cin>>S.name;
cout<<"Enter students ID: ";
cin>>S.ID;
cout<<"The student's name is "<< S.name<<endl;
cout<<"The student's ID is "<< S.ID<<endl;
return 0;
}
In your main function you are trying to access the name and IDmember of your class. Which are private... Since you are outside the scope of the class Student, the compiler shouts at you.
You should do this (as you've implemented setters and getters):
int ID(0);
std::string name;
std::cin >> name;
S.setName(name);
std::cin >> ID;
S.setID(ID);
You have to access your private fields using setters/getters to set or retrieve their values, you can't use them with the class dot notation because they're private and you can access to them only using public methods
What's wrong : You are accessing private members without using a class member function (outside of the class scope).
Private members are useful when you want to protect a value from uncontrolled access. Like when the modification of a value must undergo a certain verification (which would be implemented in class functions).
In your code, you made sure name and ID are private, which means both can only be accessed using class functions (like the constructor or the getter and setter).
If you wanted, you could create a class named classroom (which would contain many students, stored in a vector).
In that class, you could make sure than when a student is added, it's ID is automatically generated and does not equal any other ID. In that case, it would be important to put the student vector private since it would require some sort of validation.
class Student
{
private: // anything that wants to access members below
// this must be defined as a class member, or the equivalent
string name;
int ID;
public:
void setName(string); // can access private members
string getName(); // can access private members.... should be const
void setID(int); // can access private members
int getID(); // can access private members, should be const
};
I have a data structure "Person"
struct Person
{
protected:
string name;
int age;
string address;
...
}
I want to create "views" around this structure to separate out access to different member variables:
class PersonRead: public Person
{
public:
string getName() {..}
int getAge() {...}
...
}
class PersonUpdate: public Person
{
public:
void setAddress( string address_ ) {...}
void setAge( int age_ ) {...}
...
}
I use this to only expose those methods/variables which are really required:
int main()
{
...
writePersonDataToFile ( (PersonRead) personObj );
updatePersonData ( (PersonUpdate) personObj);
...
}
Though the above code serves my purpose, there are several issues including:
The public inheritence here is not exactly an 'is-a' relationship
I need to derive IndianPerson from Person, and all the corresponding interfaces. This leads to bad diamond pattern:
struct IndianPerson: public Person {};
class IndianPersonRead: public IndianPerson, public PersonRead {}; //Person Class common, Diamond pattern here!
Is there a name for such a design pattern? What are better ways to implement this pattern? I have a feeling Policy classes might help, but cant figure out how to implement this
Any examples would be great help
For your scenario this might seem like overkill but, if you want fine grained control over which classes can call different methods on your class the c++ client-attorney idiom idiom might be appropriate.
For a detailed description of this idiom see http://drdobbs.com/184402053
Here is a rough example (note: this has not been compiled, although it is based on production code I am currently using):
class Person
{
public:
/// constructor destructor etc:
private:
string getName() { return name; }
public:
/// Writer Attourney that access to allows class PersonReader access
/// to getXXX functions
class ReaderAttorney
{
private:
/// Add additional reader member functions...
static string readName( Person& p )
{
return p.getName();
}
// Make any classes that shuold be allowde read access friends of the
// attorney here
friend class PersonReader;
};
/// Writer Attourney that access to allows class PersonWriter access
/// to setXXX functions
class WriterAttorney
{
private:
/// Add additiona reader member functions...
static string setName( Person& p, const string& newName )
{
p.setName( newName );
}
friend class PersonWriter;
};
private:
string name;
int age;
string address;
};
This can be used as follows:
void PersonWriter::setPersonDetails( const string& name, int age .... )
{
// PersonWriter is a frend of WriterAttorney and is granted access
Person::WriterAttorney::setName( name );
Person::WriterAttorney::setName( age );
// Note this will fail, since PersonWriter is not a friend of
// ReaderAttorney, ergo it is not granted read permission:
Person::ReaderAttorney::readName();
}
I think that your approach is not correct at all: PersonRead and PersonUpdate are not Persons. They read and modify Person data but are not really Person.
In the same way, IndianPersonRead and IndianPersonUpdate are not an IndianPerson.
I separate this relationship in following:
PersonRead use Person
PersonUpdate use Person
IndianPerson inherits from Person: is a Person
IndianPersonRead inherits from PersonRead and use IndianPerson
IndianPersonUpdate inherits from PersonUpdate and use IndianPerson
I show an example of my apporach:
#include <string>
#include <iostream>
using namespace std;
struct Person
{
string getname() const { return name; }
string getaddress() const { return address; }
void setaddress(const string & address_) { address = address_; }
void setname(const string & name_) { name = name_; }
protected:
string name;
int age;
string address;
};
class PersonRead
{
public:
string getname(const Person & p) { return p.getname(); }
};
class PersonUpdate
{
public:
void setAddress(Person & p, const string & address_ ) {p.setaddress(address_); }
void setname(Person & p, const string & name_ ) {p.setname(name_); }
};
struct IndianPerson : public Person
{
string gettribe() const { return tribe; }
void settribe(const string & tribe_) { tribe = tribe_; }
protected:
string tribe;
};
struct IndianPersonRead : public PersonRead
{
public:
string gettribe(const IndianPerson & p) const { return p.gettribe(); }
};
struct IndianPersonUpdate : public PersonUpdate
{
public:
void settribe(IndianPerson & p, const string & t) { p.settribe(t); }
};
int main(int argc, char **argv)
{
IndianPerson ip;
IndianPersonUpdate ipU;
IndianPersonRead ipR;
ipU.settribe(ip, "Cheroki");
ipU.setname(ip, "Charly");
cout << ipR.getname(ip) << " : " << ipR.gettribe(ip) << endl;
}
First of all I will agree with the Tio's point of view PersonUpdate is not a Person so there is a wrong inheritance usage. Also I believe that you need to make your classes with target to represent the real world so classes like PersonUpdate are wrong because they represent the action and not the object.
In your case one solution could be to use the visitor design pattern, so the Person could accept a especially designed IPersonStream interface in order to perform the serialization in classes which will implement this interface.
Person stream will accept the persons attributes on it or for good the Person's memento take a look on memento design pattern, and serialize it to xml or whatever you want.
I don't have a design pattern name, but to resolve your concerns, I would swap the inheritance relation and let Person inherit from the PersonReader and PersonWriter interfaces. This way, objects that must only read from Person use the PersonReader interface and as such promises to not change it.
By making every member of Person private, you can even make sure that Person is not accessed in another way, but then every class that inherits from Person should have these members private.