* DEFSNG is normally the Qbasic default type assignment for undefined variables without type suffixes.
* DEFSNG sets the [[type]] of all variable names with the starting letter(s) or letter ranges when encountered in the progression of the program(even in conditional statement blocks not executed and subsequent [[SUB]] procedures).
* '''Qbasic's IDE may add DEF statements before any [[SUB]] or [[FUNCTION]]. QB64(like QB) will change all variable types in subsequent sub-procedures to that default variable type without giving a [[ERROR Codes|"Parameter Type Mismatch"]] warning or adding the proper DEF statement to subsequent procedures! If you do not want that to occur, either remove that DEF statement or add the proper DEF type statements to subsequent procedures. May also affect [[$INCLUDE]] procedures!'''
* '''Warning: Qbasic keyword names cannot be used as numerical variable names with or without the type suffix!'''