Re: Reversing a String
Re: Reversing a String
- Subject: Re: Reversing a String
- From: Robert Marini <email@hidden>
- Date: Wed, 31 Dec 2008 01:22:42 -0500
In general, it would perhaps be best to create a c string from the
NSString using the proper text encoding and then iterating through the
C string in reverse, appending each character to an NSMutableString.
Iterating through each character of an NSString is likely to be slow
and the usage of characterAtIndex is certainly more than pointer
arithmetic.
-rob.
On Dec 31, 2008, at 12:59 AM, Adam R. Maxwell wrote:
On Dec 31, 2008, at 4:23 PM, Ron Fleckner wrote:
const int stringLength = [aString length];
char reverseChars[stringLength];
for (i = stringLength - 1, j = 0; i >= 0; i--, j++)
{
char c = [aString characterAtIndex:i];
reverseChars[j] = c;
}
Unfortunately, this is not correct; -[NSString characterAtIndex:]
returns a unichar, which is not a char. In addition, it will give
odd results for composed characters. Depending on what you want,
you might be able to use rangeOfComposedCharacterAtIndex:.
I'd also use NSMutableString instead of a stack buffer of chars,
since this looks like a buffer overflow (unless I'm missing
something):
reverseChars[j] = '\0';// create a C (UTF8) string by adding a
null char
--
Adam
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