What is "quickbasic"

Microsoft QuickBASIC (also QB) is an Integrated Development Environment (or IDE) and compiler for the BASIC programming language that was developed by Microsoft. QuickBASIC runs mainly on DOS, though there was a short-lived version for Mac OS. It is loosely based on GW-BASIC but adds user-defined types, improved programming structures, better graphics and disk support and a compiler in addition to the interpreter. Microsoft marketed QuickBASIC as the introductory level for their BASIC Professional Development System. Microsoft marketed two other similar IDEs for C and Pascal, viz QuickC and QuickPascal.