QuickBasic was an enhanced version of Basic published by Microsoft that supported optionally compiling programs into executables, rather than running then in the interpreter interactively. Ok LIST PRINT 2 + 7 30 PRINT 2 + 7 10 I = 42 20 PRINT I + 12 LIST RUN 20 LIST You are typing on a typewriter – with a roll of paper instead of a screen – and the typewriter responds back at you by printing on the paper as well!: Welcome to B.A.S.I.C. Remember: there are no cursor keys or screens. Why do something so arcane? because when Basic was invented it was intended to be interactive, in a world where the only form of interactivity was a command-line prompt, on a teletype-style printing terminal.Ī typical Basic session might have looked like this, where > stands for a command processor prompt (this is made-up, but close enough to how it worked).
The line number told the Basic interpreter two things: a) that you were storing the line (otherwise the interpreter would execute it immediately), and b) in what position of the program the line belonged.
In MS-Basic, like in every other Basic implementation of the era, every line you added to a program had to start with a line number. The syntax of VBA/VB6 is designed to be backwards-compatible with the syntax of QuickBasic, and before that with the syntax of GW-Basic/MS-Basic, which dates to the late 1970’s and even earlier: the original Dartmouth BASIC Language was created in the ’60s. I understand your dislike of the answer “start the line with a line number”, but you can’t argue with facts.
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