C++ '101'

[robbiegregg]

Hi all

I have a general question as to how I should implement the following in Visual C++ (v6):

I would like to read in a whole bunch of data from a file and save to memory so I can then perform various calculations, etc. My preferred way is to create a custom structure and define a 1-D array at the start of the file such that it is accessible by all later functions (i.e. OnInitDialog, OnLoadFile, CalculateSomething, etc). A function "OnLoadFile" reads in the data and saves to the 1D array "itemlist" and other functions such as "CalculateSomething" takes this data and performs various calculations / manipulations.

struct StructItem
{
     int value1;
     int value2;
     float values[10];
};

#define MAXSIZE 100000
StructItem itemlist[MAXSIZE];

BOOL CProgDlg::OnInitDialog()
{
   .....
}

void CProgDlg::OnLoadFile()
{
   // Code here to read in ASCII file and save data to the variables in itemlist[] ..
   ..
}

void CProgDlg::CalculateSomething()
{
   // Code here to perform some task on the variables in itemlist[] ..
   ..
}

My problem is that I do not know how I can dynamically set the size of the variable itemlist. For example the data set might be really large or really small so I find myself needing to set MAXSIZE large enough to cover all possibilities. Does anyone know a way of defining a variable that can change its size dynamically as and when required? The variable has to be accessible throughout hence why I don't define the variable "itemlist" in the function "OnLoadFile" dynamically using "StructItem *itemlist = new StructItem[NUM_ITEMS];"

Thanks

Robbie