Sets the symbol to be used for indicating missing data fields in a case file created by Netica. Data is "missing" when Netica has to provide the value for a node, and that node doesn't have a finding entered.

For newchar, pass the ascii character code. It must be one of asterisk * (42), question mark ? (63), space (32) or absent (0). It cannot be space or absent unless the delimiter symbol is a comma (see SetCaseFileDelimChar_ns).

newchar will only be used by Netica for creating case files; while reading them it will understand any of the above choices.

It returns the old symbol being used for this purpose. If QUERY_ns is passed for newchar, then the old value is returned without changing it.