Thread: Classes and member functions

Hi Folks,
I'm still trying to get my head around Classes...

Specifically, I am having problems defining functions within a class. I can only seem to define them outside a class. If i put them in a class I get compiler errors.

Here is my code. How would I change this to put definitions within the person class?

Also, I get errors if I define the destructor just as ~person();

Code:

////////////////////////////////////////////////////
// Demonstrates Class, Member Data, Member Functions
////////////////////////////////////////////////////

#include <iostream>
#include <string>
#include <vector>

using namespace std;

///////////////////////////////////////
// Define person class
///////////////////////////////////////

class person
{
    public:
           /////////////////////////////////
           // constructor
           /////////////////////////////////
           
           person(int age)
           {
           itsname="undefined";
           itsage=age;
           }
           
           /////////////////////////////////              
           // destructor
           /////////////////////////////////
           
          ~person()
          {
          
          }
    
           /////////////////////////////////
           // function prototypes
           /////////////////////////////////

           void setage(int age);
           int getage();
           void setname(string name);
           string getname();
           

    private:
            string itsname;
            int itsage;
};
        
/////////////////////////////////////////////////////////////////////////


           /////////////////////////////////
           // function definitions           
           /////////////////////////////////
           
           
           void person::setage(int age)
                {
                itsage=age;
                }
                
           int person::getage()
                {
                return itsage;
                }
               
           void person::setname(string name)
                {
                itsname=name;
                }
                
           string person::getname()
                {
                return itsname;
                }
                               
/////////////////////////////////////////////////////////////////



///////////////////////////////////////
// Main Program
///////////////////////////////////////
        
int main()
{
            
            /////////////////////////////////////////
            // test class
            /////////////////////////////////////////
            
        
            // create person class called test
        
            person test(9999);                                      
        
        
            // change member variables and print to test
        
            cout << "initial age = " << test.getage() << "\n";    
            
            test.setage(13);
            cout << "altered age = " << test.getage() << "\n";
            
            cout << "initial name = " << test.getname() << "\n";
            
            test.setname("bobbins");
            cout << "altered name = " << test.getname() << "\n";
            
                
            /////////////////////////////////////////
            // wait for user to end program
            /////////////////////////////////////////
               
            cin.get();
            return 0;
}

Code:

class person
{
    public:
           
           person(int age)
           {
           itsname="undefined";
           itsage=age;
           }
           
           /////////////////////////////////              
           // destructor
           /////////////////////////////////
           
          ~person()
          {
          
          }
    
           void setage(int age)
           {
                itsage=age;
           }

           int getage()
          {
                return itsage;
          }
           
           void setname(string name)
           {
                itsname=name;
           }

           string getname()
           {
                return itsname;
           }
           

    private:
            string itsname;
            int itsage;
};

I would also add a few const qualifiers, and place semi-colons between the function definitions, but that's my personal preference.

And I would avoid having "using namespace std;" before the class declaration (yes, that means typing "std::string" instead of "string"). That is a stylistic thing, but has a significant chance of becoming a technical problem if the class declaration is moved into its own header file in future, and that header is #include'd by multiple source files.

Got it!

Many thanks for your help!