S$ = "alphaBETA"

UP$ = "" : FOR I = 1 TO LEN(S$) : C = ASC(MID$(S$, I, 1)) : UP$ = UP$ + CHR$(C - (C > 96 AND C < 123) * 32) : NEXT I : ? UP$

LO$ = "" : FOR I = 1 TO LEN(S$) : C = ASC(MID$(S$, I, 1)) : LO$ = LO$ + CHR$(C + (C > 64 AND C < 91) * 32) : NEXT I : ? LO$