QBasic came complete with four pre-written example programs. Until MS-DOS 7, MS-DOS Editor and Help required QBasic: the EDIT.COM and HELP.COM programs simply started QBasic in editor and help mode only, and these can also be entered by running QBASIC.EXE with the /EDITOR and /QHELP switches (i.e., command lines QBASIC /EDITOR and QBASIC /QHELP). However, if used on any 8088/ 8086 computers, or on some 80286 computers, the QBasic program may run very slowly, or perhaps not at all, due to DOS memory size limits. QBasic (as well as the built-in MS-DOS Editor) is backwards-compatible with DOS releases prior to 5.0 (down to at least DOS 3.20). Starting with Windows 2000, Microsoft no longer includes QBasic with their operating systems, but still makes it available for use on newer versions of Windows. QBasic 1.1 is included with MS-DOS 6.x, and, without EDIT, in Windows 95, Windows 98 and Windows Me.
eComStation and ArcaOS, descended from OS/2 code, include QBasic 1.0. IBM recompiled QBasic and included it in PC DOS 5.x, as well as OS/2 2.0 onwards. Version 1.0 was shipped together with MS-DOS 5.0 and higher, as well as Windows 95, Windows NT 3.x, and Windows NT 4.0. It was based on the earlier QuickBASIC 4.5 compiler but without QuickBASIC's compiler and linker elements. QBasic was intended as a replacement for GW-BASIC. It supports various inbuilt functions.įor 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. QBasic has limited support for user-defined data types ( structures), and several primitive types used to contain strings of text or numeric data. Line numbers, a concept often associated with BASIC, are supported for compatibility, but are not considered good form, having been replaced by descriptive line labels. Like QuickBASIC, but unlike earlier versions of Microsoft BASIC, QBasic is a structured programming language, supporting constructs such as subroutines. Code entered into the IDE is compiled to an intermediate representation (IR), and this IR is immediately executed on demand within the IDE. QBasic is an integrated development environment (IDE) and interpreter for a variety of dialects of BASIC which are based on QuickBASIC. MS-DOS, Windows 95, Windows 98, Windows Me, PC DOS, OS/2, eComStation, ArcaOS
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