string directory_name = "Data";
string file_name = "EURGBP30-1.csv";
int file_handle = FileOpen(file_name, FILE_READ|FILE_CSV,",");
if(file_handle != INVALID_HANDLE)
PrintFormat("Fileopen. Name : %s", file_name);
data_size = 3;
for(i = 0; i< data_size; i++)
The prices for the terminals are coming from the broker including with their properties (I assume your data don't have any properties, just prices).
All the functions like iClose(), ... accesses these data from the broker.
Beside that you can't access folder outside the mt4-sandbox with the mt4 file functions - you would have to use the functions of the kernel32.dll
Maybe you can create offline charts (search here or google!).