NSString中識別中文字符

UTF8編碼：漢字佔3個字節，英文字符佔1個字節

NSString *text = @"i'm a 蘋果。...";
int length = [text length];

for (int i=0; i<length; ++i)
{
NSRange range = NSMakeRange(i, 1);
NSString *subString = [text substringWithRange:range];
const char *cString = [subString UTF8String];
if (strlen(cString) == 3)
{
NSLog(@"漢字:%s", cString);
}
}