Using Variables

gregarion · 02-04-2010, 12:41 PM

Hey guys im facing a problem in declaring variables. i have a few classes like the one below...

Code:

#ifndef _FINANCE_H
#define	_FINANCE_H

#include <string>
#include <iostream>
#include <fstream>
#include <stdlib.h>

using namespace std ;


class  readStraitsTimesIndex
{
    public:
         void StraitsTimesIndex(fstream&) ;
    private:
};

class readDow
{
    public:
        void Dow(fstream&) ;
    private:
 };

what i am trying to do is to use a value which is being the output of one of the class class and to be displayed into the other class. I tried using an object member like the one below ,

Code:

class  readStraitsTimesIndex
{
    public:
         void StraitsTimesIndex(fstream&) ;
String value ;
    private:

};

and then assigned a value to it, but it will only work within the class. how do i go about saving a certain variable and using it in all the classes

neonsignal · 02-04-2010, 02:26 PM

You can access public variables from a class just as you would the member functions, eg:

Code:

readStraitsTimesIndex test;
std::cout << test.value << std::endl;

However, generally speaking, variables in an object oriented program should be private to their classes. Instead, one implements member functions that return the information that you require in another class.

This may begin by being as simple as a function that returns the value. But by having a function, the implementation can be changed over time without changing the outside interaction with the class.

If you find you have a lot of these 'global' variables, then you have probably not understood object oriented design.