QBasic's an IDE and interpreter for a variant of the BASIC programming language which's based on QuickBasic. Code entered into the IDE's compiled to an intermediate form, and this intermediate form's immediately interpreted on demand within the IDE. For its time, QBasic provided a state-of-the-art IDE, including a debugger with features such as on-the-fly expression evaluation and code modification that were still relatively unusual more than ten years later. Like QuickBASIC, but unlike earlier… (More on Qbasic)