Compare string to NSArray - iphone

Question

I have to classes the Checkin and the FriendList.
Checkin.h
#interface Checkin : NSObject {
NSString *name;
NSString *profID;
NSString *place;
NSString *photoURL;
NSMutableArray *taggedID;
NSMutableArray *taggedName;
and the Friendlist.h
#interface FriendList : NSObject {
NSString *name;
NSString *profID;
}
What I am trying to do is to compare each checkin.profid(approximately 5-6) with the friendlist.h(200-5000).
I tried to do it with for loop but when checks the second checkin.profid is crashing.
This is my method:
for(int i=0; i<[checkinArray count];i++){
Checkin *tempcheck = [[Checkin alloc] init];
tempcheck = [checkinArray objectAtIndex:i];
for(int j=0;j<[friendsArray count]; j++){
NSLog(#"count %d",j);
FriendList *tempfriend = [[FriendList alloc] init];
tempfriend = [friendsArray objectAtIndex:j];
if([tempcheck.profID isEqualToString:tempfriend.profID]){
NSLog(#"Find prof id same for : %#",tempcheck.name);
break;
}
else
NSLog(#"Not found id same for: %#",tempcheck.name);
[tempfriend release];
}
[tempcheck release];
}
}
Is there any better way to do this comparison? Because its also too slow.
Thank you in advance

Answer 1

this isn't going to be helping:
Checkin *tempcheck = [[Checkin alloc] init];
tempcheck = [checkinArray objectAtIndex:i];
And
FriendList *tempfriend = [[FriendList alloc] init];
tempfriend = [friendsArray objectAtIndex:j];
there's no reason to alloc them: just set it to be the object at the desired index:
Checkin *tempcheck = [checkinArray objectAtIndex:i];
would be better. As for doing the finds, why not loop through the checkins and for each checkin.profId instantiate a new NSPredicate to find the profId through the friendlist. Try [NSPredicate filterWithFormat:#"(profId = %#)"];
and then use filteredArrayUsingPredicate on your array.

Answer 2

Your memory management is all broken. When you do something like this:
Checkin *tempcheck = [[Checkin alloc] init];
tempcheck = [checkinArray objectAtIndex:i];
What you are doing is creating an object and then assigning the pointer to the object in the checkin array. This causes a memory leak right there.
Then, later on when you do:
[tempcheck release];
you're actaully calling release on the object in the array, not the one you alloc'd earlier. This presumably leads the the object in the array being garbage-collected and then when you try and access it the second time round you get a crash.
Remove the allocs & releases and just do something like this:
Checkin *tempcheck = [checkinArray objectAtIndex:i];