54. Capitals conversion
    ~~~~~~~~~~~~~~~~~~~
This is a Function for converting a string to all upper-case letters; figures
and punctuation are not affected. This saves you having to test for, say,
"YES" and "yes", in response to a keyboard input. To make sure a string is
all capitals, just use A$=FNcaps(A$) . By making the alterations suggested in
the REM statement, you can make it change to lower-case instead.

 100 DEF FNcaps(text$):LOCAL letter%,char%,result$
 110 FOR letter%=1 TO LEN(text$)
 120 char%=ASC(MID$(text$,letter%,1))
 130 IF char%>96 AND char%<123 THEN char%=char%-32
 140 REM change 96 to 64, 123 to 91, and -32 to +32
 150 result$=result$+CHR$(char%):NEXT:=result$