tasks a-s

Task/Reverse-a-string/XPL0/reverse-a-string.xpl0

@@ -0,0 +1,23 @@
+include c:\cxpl\codes;  \intrinsic 'code' declarations
+string 0;               \use zero-terminated strings, instead of MSb terminated
+
+func StrLen(Str);       \Return the number of characters in an ASCIIZ string
+char Str;
+int  I;
+for I:= 0 to -1>>1-1 do
+        if Str(I) = 0 then return I;
+
+func RevStr(S);         \Reverse the order of the bytes in a string
+char S;
+int  L, I, T;
+[L:= StrLen(S);
+for I:= 0 to L/2-1 do
+        [T:= S(I);  S(I):= S(L-I-1);  S(L-I-1):= T];
+return S;
+];
+
+[Text(0, RevStr("a")); CrLf(0);
+ Text(0, RevStr("ab")); CrLf(0);
+ Text(0, RevStr("abc")); CrLf(0);
+ Text(0, RevStr("Able was I ere I saw Elba.")); CrLf(0);
+]