Declaring Variables

[gregarion]

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:
};
[/CODE]

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:

};[/CODE]

and then assigned the output of that class to the variable(value) , but it will only work within the class. how do i go about saving a certain variable from the output of a certain class and using it for the other variables.

[Maximilien]

not certain I understand completely your problem, wchich sounds a lot like a very basic problem. something like this? :

class A
{
private:
int m_a;
public:
int f(){return m_a;};
};

class B
{
private:
int m_b;
void f()
{
A a;
m_b = a.f();
};
};

or something like this?:

class A
{
private:
int m_a;
public:
int GetA(){return m_a;};
};

class B
{
private:
int m_b;
public:
void SetB( int b){ m_b = b;};
};

void main()
{
A a;
B b;
b.SetB( a.GetA() );
}

depending on the relation between A and B, this could be done in a multitude of different ways.

This signature was proudly tested on animals.

[gregarion]

Sorry , let me try to make it clear. For example, in class A, it will extract a certain value. What i want to do is to save this value in a way that it can be called out in any other classes, either for just displaying the information or to do some calculations.

[Lost User]

You need to add some extra methods in your class to return the data in whatever way the caller needs. Try rereading the C++ guide(s) or books on classes and how to use them.

MVP 2010 - are they mad?

[gregarion]

What should i be looking for exactly when i read the book?

[Maximilien]

Well, you need something to "hold" the data that class A will retrieve. for example If class A is simply reading data from a file, then class B could hold the data for it. For example in MFC, you have the class CStdioFile that only reads text from a file, but in a software that use that class, I will need something to hold the text (for example a vector of text lines that are read). Another variation, sometimes if the class is more or less specialized it could be used to read and hold data at the same time. for example I could have a class MyStdIoFile that is derived from CStdioFile that will not only read from the file, but store the data internally.

class MyStdIoFile : public CStdioFile
{
public:
Read( CString path ){/* call code from CStdIoFile to read and put it in m_Data*/ };

protected:
vector m_Data;
}

again, there are tons of different ways of doing this, it's more a question of design than a question of code; who reads, who writes. who keep the data, who display the data, how is it read, how is it kept, how is it displayed. Take a piece of paper and draw littles boxes representing your different objects and draw lines and arrows between them to show the relationships.

This signature was proudly tested on animals.

[gregarion]

Okay , that sounds complicated. Basically why i need it to store the output given out in a certain class is because i need to use it for cppunit testing later on. Basically, each class in my project will give out a certain output based on the document it reads For example, classA gives an output of 333. ClassB gives an output of 434. what i was trying to do is to try to save this values in a way that when i write my cppunit, i can use it to check if it is equal to the hardcoded input.

[Lost User]

gregarion wrote:

What should i be looking for exactly when i read the book?

The fact that you need to ask this question suggests you need to look at everything. If you do not understand how classes hold their data and how they return it to other objects/callers then you are missing the fundamentals of object oriented programming; a significant hole in your knowledge.

MVP 2010 - are they mad?

[Rozis]

Richard MacCutchan wrote:

The fact that you need to ask this question suggests you need to look at everything. If you do not understand how classes hold their data and how they return it to other objects/callers then you are missing the fundamentals of object oriented programming; a significant hole in your knowledge.

I vote a 10 for this one! :)

[Lost User]

;) :-\

MVP 2010 - are they mad?