EDIT 1: Updated function with faster searching code. Thanks, Na_trium!
EDIT 2: Fixed issue with strings being replaced.
Ever heard of ROT13? It's a ciphering function! It maps letters of the alphabet A-M to N-Z, and vise versa. Here's a simple function to implement it into SmileBASIC 4.
First, let's set up our function. We'll be using
OPTION STRICT so that our variables must be defined before using them. Go into the editor, and type this:
OPTION STRICT
COMMON DEF ROT13$(S$)
This will set up a function,
ROT13$(String), which will convert
String to its ROT13 counterpart.
Next, let's set up our variables. These will be used in our code.
OPTION STRICT
COMMON DEF ROT13$(S$)
VAR I=0
VAR R$=S$+""
VAR L=0
VAR ALPHABET$="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
VAR ROT13$="NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm"
You may have noticed the two really long variables,
ALPHABET$ and
ROT13$ (not to be confused with our ROT13 function). These are dictionaries. We'll scan through each letter of the string to find which one matches one of the letters in the
ALPHABET$ variable, and find its matching ROT13 counterpart using the
ROT13$ variable. Let's implement this!
OPTION STRICT
COMMON DEF ROT13$(S$)
VAR I=0
VAR R$=S$+""
VAR L=0
VAR ALPHABET$="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
VAR ROT13$="NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm"
FOR I=0 TO LAST(R$)
L=INSTR(0,ALPHABET$,R$[I])
IF L!=-1 THEN
R$[I]=ROT13$[L]
ENDIF
NEXT
There! Now our function will do what I mentioned. All we have to do now is have our function return the converted string and end.
OPTION STRICT
COMMON DEF ROT13$(S$)
VAR I=0
VAR R$=S$+""
VAR L=0
VAR ALPHABET$="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
VAR ROT13$="NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm"
FOR I=0 TO LAST(R$)
L=INSTR(0,ALPHABET$,R$[I])
IF L!=-1 THEN
R$[I]=ROT13$[L]
ENDIF
NEXT
RETURN R$
END
That's it! Now our function is ready to go. Run the code to register the function, and type this into direct mode:
?ROT13$("Hello world!")The output should be:
Uryyb jbeyq!
