Try this:
(defun c:test (/ DimAssocValue)
(initget "0 1 2")
(setq DimAssocValue (getkword "\n0, <1>, or 2: "))
(if (member DimAssocValue '("0" "1" "2"))
(setvar "dimassoc" (atoi DimAssocValue))
)
(prompt (strcat "\n" "DimAssoc Value = " (itoa (getvar "dimassoc"))))
(setvar "dimassoc" 1)
(princ)
)