[fpc-pascal] High() and Low() for empty dynamic arrays

[Jürgen Hestermann]

Am 2014-02-08 17:05, schrieb Florian Klaempfl:
 > Here:
 > var MyArray : array of longint;
 > begin
 >   writeln(low(MyArray));
 >   writeln(high(MyArray));
 > end.
 > prints
 > 0
 > -1

Hmm.
I was under the impression that both give back zero.
But you are right.
A closer look showed that the error I got for arrays of zero length
came from the fact that I used a Cardinal type variable for the for-loop:

-------------------------------------------
var i : Cardinal;

for i := Low(MyArray) to High(MyArray) do ...
-------------------------------------------

which raises an exception when the array is empty
but works ok in all other cases.
Thanks for pointing me to my fault.



 > Unfortunatly you posted not a complete example which shows the behaviour but only uncompilable code snippts.
 > Post always complete examples when discussing strange behaviour.

You mean I should post thousands of code lines?