Introduction to QBASIC
QBASIC is a high level programming language. It works in an Integrated Development Environment (IDE). QBasic window is used to write the QBasic programs. The various components of a QBasic window are menu bar, status bar, sub menu bar, program title, program mode and immediate mode. Editor is used to type, edit, debug and execute the program. Editor is divided into two parts: program mode and immediate mode. In program mode, commands are not executed immediately and are stored in computer’s memory. In immediate mode, commands are executed immediately and are not stored in computer memory.
To write a QBASIC program, click on Start point to All Programs and select MS QBASIC. The QBASIC window appears with a Welcome dialog box. Press Esc key to hide the welcome dialog box. Type the program in the QBASIC editor. To save a program, click on File menu and select Save As option. Type the filename and press Enter. The file will automatically be saved with .bas extension. There are different ways to run a program in QBasic: By pressing F5 key, by selecting RUN menu and clicking on Start option and by typing RUN in the immediate mode and pressing the Enter key. The process of finding bugs and removing them from a program is called debugging. The element required to construct a QBASIC program consists of statements, a set of characters, constants, variables, operators and expressions.