my first oop based program

i'd like to know how to make the same pointer points to differents types of vars,
if you read the code, you'll see the comment I NEED A SOLUTION FOR THIS, and thats where im stuck...

Code:

#include <iostream>
using namespace std;

class person
{

    public:

    person();

    string name;
    int age;
    bool sex; // true means male
    string country;

    string sexString()
    {
    string returnString;
    returnString = (this->sex == true) ? "guy" : "woman" ;
    return returnString;
    }

};

person::person()
{
    this->name = "Unnamed Person";
    this->age = 50;
    this->sex = true;
    this->country = "United States";
}

void introduce(person person)
{
    cout<<"Hi, my name is "<<person.name<<". I'm a "<<person.age<<" years old "<<person.sexString()<<", and I live in "<<person.country<<"."<<endl;
}

void callMenu(person& person)
{

    int option;
    string optionIdentifier;
    string input;
    string * pointer;

    cout<<"\n WHAT WOULD LIKE TO CHANGE?\n";
    cout<<"1. NAME\n";
    cout<<"2. AGE\n";
    cout<<"3. SEX\n";
    cout<<"4. COUNTRY\n";
    cout<<"5. NOTHING\n";

    cout<<"\nCOMMAND: ";
    cin>>option;

    switch(option)
    {
        case 1:
        optionIdentifier = "NAME";
        pointer = &person.name;
        break;

        case 2:
        optionIdentifier = "AGE";
        //pointer = &person.age;   I NEED A SOLUTION FOR THIS
        break;

        case 3:
        optionIdentifier = "SEX";
        //pointer = &person.sex; I NEED A SOLUTION FOR THIS
        break;

        case 4:
        optionIdentifier = "COUNTRY";
        pointer = &person.country;
        break;
    }

    cout<<"TYPE YOUR NEW "<<optionIdentifier<<": ";
    cin>>input;

    *pointer = input;

    introduce(person);

}

int main()
{

person someone;

introduce(someone);

callMenu(someone);

cin.get();

}

btw, advices for making the code cleaner are welcome

Just write directly to the variable you are attempting to change. For example:

Code:

case 2:
optionIdentifier = "AGE";
cin >> person.age;
break;

Also, in general it's not a good idea to make a classes member variables have public access. Read up on "encapsulation" for the reasons why.

I think the program is neat but isn't really OOP.

Using your current Person class I could make another program that introduces a person like this:

Code:

person myperson;
int option;

cout << "1 - Change name\n";
cout << "2 - Change age\n"
cout << "3 - Change gender\n";
cout << "4 - Change country\n"
cout << "5 - Change nothing\n";
cout << "Choose an option - ";

cin >> option;

switch (option) {
case 1: {
   cout << "Enter a new name: ";
   cin >> myperson.name;
}
break;
case 2: {
   cout << "Enter a new age: ";
   cin >> person.age;
}
break;
case 3: {
   string gender;
   cout << "Enter a new gender ("guy" or "woman");
   cin >> gender;
   myperson.sex = gender == "guy";
}
break;
case 4: {
   cout << "Enter a new country: ";
   cin >> myperson.country;
}
break;
case 5:
default:
break;
}

introduce (myperson); 
cin.get (); // for a pause

You'll get to change one thing about him before you meet him, which is exactly how your program seems to work now.

There's nothing particularly object oriented about this, anyway, but it is rather strange that person is a class that exposes its data to the rest of the program. The code sample doesn't need to be found in a main() function. I could change the details of a person anywhere, and in any way I wanted.

My advice for the program is to throw it away. My advise for you is to learn more about OOP. There are no shortage of tutorials (or entire books), just STFW.

I've upgraded my code, i'll read about encapsulation later, thanks.

I still haven't managed to make the pointer work on multiple data types though...

Code:

#include <iostream>
using namespace std;

class person
{

    public:

    person();

    string name;
    int age;
    bool sex; // true means male
    string country;

    string sexString()
    {
    string returnString;
    returnString = (this->sex == true) ? "guy" : "woman" ;
    return returnString;
    }

};

person::person()
{
    this->name = "Unnamed Person";
    this->age = 50;
    this->sex = true;
    this->country = "United States";
}

void introduce(person person)
{
    cout<<"\nHi, my name is "<<person.name<<". I'm a "<<person.age<<" years old "<<person.sexString()<<", and I live in "<<person.country<<"."<<endl;
    cin.get();

}

void callMenu(person& person)
{

    int option;
    string optionIdentifier;
    string input;
    string * pointer;

    int numberOfChanges = 0;

    do{
    cout<<"\n WHAT WOULD YOU LIKE TO CHANGE?\n";
    cout<<"1. NAME\n";
    cout<<"2. AGE\n";
    cout<<"3. SEX\n";
    cout<<"4. COUNTRY\n";
    cout<<"5. NOTHING\n";

    cout<<"\nCOMMAND: ";
    cin>>option;

    switch(option)
    {
        case 1:
        optionIdentifier = "NAME";
        pointer = &person.name;
        break;

        case 2:
        optionIdentifier = "AGE";
        //pointer = &person.age;
        break;

        case 3:
        optionIdentifier = "SEX";
        //pointer = &person.sex;
        break;

        case 4:
        optionIdentifier = "COUNTRY";
        pointer = &person.country;
        break;
    }

    if(option != 5)
    {
    cout<<"TYPE YOUR NEW "<<optionIdentifier<<": ";
    cin>>input;

    *pointer = input;

    numberOfChanges++;

    }

    }while(option != 5);


    introduce(person);

}

int main()
{

person someone;

introduce(someone);

callMenu(someone);

cin.get();

}

Do what I suggested in my post...

You can't do it your way since the data aren't all the same type. You could do it your way with a more advanced technique, but then, what is the point?
bithub's example is easier, so I'd suggest you use that instead.

Other suggestions:


#1.

Code:

#include <iostream>
using namespace std;

class person
{
    ...

    string name;

    ...

    string country;

    ...

Make sure you've also got #include <string> in addition to the <iostream> header. Your implementation may pull in the necessary header for the string object to work but you really do not want to rely on this. Since you're using string containers, include the string header.



#2.

Code:

class person
{

    public:

    person();

    ...

};

person::person()
{
    this->name = "Unnamed Person";
    this->age = 50;
    this->sex = true;
    this->country = "United States";
}

For such a constructor, the preferred method of initialization is to use something a bit different, for example:

Code:

class person
{

    public:

    person() : name("Unnamed Person"), age(50), sex(true), country("United States") {};

    ...
    
};

#3.

Code:

class person
{
    ...

    string sexString()
    {
    string returnString;
    returnString = (this->sex == true) ? "guy" : "woman" ;
    return returnString;
    }

};

Member functions that do not alter the class (change the value of any of its member variables) should be declared const. The function can also be simplified a bit:

Code:

class person
{
    ...

    string sexString() const
    {
        return sex ? "guy" : "woman" ;
    }

};

#4.

Code:

void introduce(person person)
{
    cout<<"\nHi, my name is "<<person.name<<". I'm a "<<person.age<<" years old "<<person.sexString()
        <<", and I live in "<<person.country<<"."<<endl;
    cin.get();

}

When passing objects into function, prefer to use a reference parameter. Also, since the function does not do anything to alter the member variables of the passed in object, it should be passed in as const:

Code:

void introduce(const person& person)
{
    cout<<"\nHi, my name is "<<person.name<<". I'm a "<<person.age<<" years old "<<person.sexString()
        <<", and I live in "<<person.country<<"."<<endl;
    cin.get();

}