This constructor set the corresponding attributes to the values of incoming arguments and sets the data attribute to NULL.

'''void* Data();'''

These are pure virtual methods enforcing the creation of the identical methods in the derived classes. This make the IO_Field class an abstract class.

Note: The purpose of passing a IO_Form pointer to the Edit method, is to make the future Edit methods capable of sending a message (errors and help messages)to the Screen they are being Edited on.

===IO_Frame===