Factorial in Basic

Example for versions QBasic 1.1, QuickBASIC 4.5

This example uses iterative factorial definition. Arithmetic overflow happens when trying to calculate 13!, but different implementations handle it in different ways: QBasic reports an exception, while QuickBasic just proceeds printing negative values. 

DIM f AS LONG
f = 1
PRINT " 0 ! ="; f
FOR i = 1 TO 16:
    f = f * i:
    PRINT i; "! ="; f
NEXT i
END