Noob : Creating a global array?

Hi!

I am trying to declare a global array for use throughout a program. The program is a math question generator (sets).

My 'main' program is as follows:-

Code:

#include <cstdlib> 
#include <iostream>

#include <ctime> 

using namespace std;

int arrayname[9];

int main() 
{ 
	srand((unsigned)time(0)); 

	int random_integer; 
	cout << "Given the sets A and B, where:-" << endl << endl << endl << "A = {";
	for(int index=0; index<5; index++)
	{ 
		random_integer = (rand()%9)+1; 
		arrayname[index] = random_integer;
		cout << arrayname[index] << ", ";

	} 
	cout << "}" << endl << endl << "and" << endl << endl << "B = {";

	for(int index=6; index<10; index++)
	{ 
		random_integer = (rand()%9)+1; 
		arrayname[index] = random_integer;
		cout << arrayname[index] << ", ";

	} 
	cout << "}";
	cout << arrayname[index] << "test";
	cout << endl << endl << endl << endl;

	system("pause");
}

I have never created another file for use during a program, I found a tutorial saying I should declare the global array in a separate header file, I've made this:-

Code:

#include <iostream>

using namespace std;

int index = 0;
extern int arrayname[index];

The header file is reporting that "'index' : undeclared identifier".

I understand global arrays are baaddd, but I'm wanting to use one at present, so in summary I'm looking for some advice on how to setup the global file correctly.

Many thanks for any advice!

Swerve.

It would be
extern int arrayname[9];

Also, putting "using namespace std" in a header file is very poor style.

Thanks Salem, will try it now.

Yeah i wondered about the namespace line, and the includes. First time created a second file, will delete the namespace.



EDIT - hmm, trying a few ways to write the file but am still getting:

'index' : undeclared identifier

I currently have the file as follows:-

Code:

#include <iostream>

int main()
{
int index = 0;
extern int arrayname[9];
}

I would guess you need to #include your header file into the one containing main.

Code:

#include <iostream>
#include "yourheaderhere.h"

int main()
{
   int index = 0;
   extern int arrayname[ 9 ];

   return 0;
}

The error is saying index is not declared because you need to include the header file you have made. I ma guessing you are using a .h extention.