NSString crash when release - iphone

Question

I use NSString to append strings, but when I release the "cacheStr" NSString, the iphone simulator crash.
Where should I put the release code ?
init code : I use three NSString to append content of the dataArray.
NSMutableArray *dataArray = [[NSMutableArray alloc] init];
NSString *cacheStr = [[NSString alloc] init];
NSString *tmpStr = [[NSString alloc] init];
NSString *notiyStr = [[NSString alloc] initWithFormat:#"This is a test message!"];
dataArray = [NSArray arrayWithObjects:
#"currency1.png",
#"currency2.png",
#"currency3.png",
#"currency4.png",
#"currency5.png",
#"xxxxxx",
#"currency1.png",
#"currency2.png",
#"currency3.png",
#"currency4.png",
#"currency5.png",
#"xxxxxx",
nil];
append string code : use for loop to append strings.
int isFailed = 0;
int countOfDataArray = [dataArray count];
if (!isFailed) {
for (int i=0; i < countOfDataArray; i++) {
if ([[dataArray objectAtIndex:i] isEqualToString:#"xxxxxx"]) {
tmpStr = [cacheStr stringByAppendingFormat:#"%#\n", [dataArray objectAtIndex:i]];
}
else {
tmpStr = [cacheStr stringByAppendingFormat:#"value %d : %#\n", i+1, [dataArray objectAtIndex:i]];
}
cacheStr = [tmpStr copy];
[tmpStr release];
}
}
tmpStr = [notiyStr stringByAppendingString:cacheStr];
release code : when I add [cacheStr release], the simulator will crash...
[dataArray release];
[notiyStr release];
// [cacheStr release]; /* crash ... */
Thanks!

Answer 1

its more simple to declare a NSString like this
NSString *tmpStr = #"This is a test message!";
then no need to release it,when you dont use alloc

Answer 2

This
NSMutableArray *dataArray = [[NSMutableArray alloc] init];
dataArray = [NSArray arrayWithObjects:
#"currency1.png",
#"currency2.png",
#"currency3.png",
#"currency4.png",
#"currency5.png",
#"xxxxxx",
#"currency1.png",
#"currency2.png",
#"currency3.png",
#"currency4.png",
#"currency5.png",
#"xxxxxx",
nil];
is strange! You are allocating a mutable array and assigning the pointer pointing to that array to an array which you do not own. It is probably already (auto)released when you try to use it. Therefore int countOfDataArray = [dataArray count]; will result in countOfDataArray being zero. Therefore cacheStr is never set. Still it shouldn't crash on releasing the cacheStr.
Change it to:
NSMutableArray *dataArray = [[NSMutableArray alloc] initWithObjects: #"currency1.png",
#"currency2.png",
#"currency3.png",
#"currency4.png",
#"currency5.png",
#"xxxxxx",
#"currency1.png",
#"currency2.png",
#"currency3.png",
#"currency4.png",
#"currency5.png",
#"xxxxxx",
nil];
and you should be fine.

Answer 3

dont use [NSString alloc] init. To use NSString value=#"Message"; No need to release it.