I've having difficulty understanding how 'extern' works.
I've searched Google but there doesn't seem to be the particular example case I'm trying

If i have a file main.cpp which references one.h
and in it i have a list named LIST1 (which is a double array of 100 x 100)
so I have double List1[100][100];

how can i use this list in one.cpp please?

```
extern double LIST1[100][100]

```

is not working :/

main.cpp:

```
#include "one.h"

extern double LIST1[100][100];

```

one.cpp:

```
void one::useList()
{
for(j = 0; j < 100; j++)
   {
     for(i = 0; i < 100; i++)
    {
         LIST1[j,i] = 0.5;
    }
 }
}

```

This is what I have.

Error I'm getting:

> 
> 1>main.obj : error LNK2001: unresolved external symbol "double (\*
>  LIST1)[100]" (?LIST1@@3PAY0GE@NA)
> 
> 
>