NSMutable Array Error
I've this code

    SBJsonParser *vol= [[SBJsonParser alloc]init];
    if (body) {
        NSArray *feeds = [vol objectWithString:body error:nil];
        NSDictionary *results = [body JSONValue];
        NSArray *subs = [results valueForKey:@"subscriptions"];
        NSArray *list;
        NSMutableArray *sub;
        
        for (NSDictionary *iscrizione in subs){
            NSLog([iscrizione objectForKey:@"title"]);
            NSLog([iscrizione objectForKey:@"htmlUrl"]);
            list=[NSArray arrayWithObjects:[iscrizione objectForKey:@"title"], [iscrizione objectForKey:@"htmlUrl"], nil];  
            [sub addObject:list];
           
        }

But when I try to add list to the NSMutableArray the program crashes. Why?
How can I insert `[iscrizione objectForKey:@"title"]` and `[iscrizione objectForKey:@"htmlUrl"]`
in a data structure? 
NSMutable Array Error
===

I've this code

    SBJsonParser *vol= [[SBJsonParser alloc]init];
    if (body) {
        NSArray *feeds = [vol objectWithString:body error:nil];
        NSDictionary *results = [body JSONValue];
        NSArray *subs = [results valueForKey:@"subscriptions"];
        NSArray *list;
        NSMutableArray *sub;
        
        for (NSDictionary *iscrizione in subs){
            NSLog([iscrizione objectForKey:@"title"]);
            NSLog([iscrizione objectForKey:@"htmlUrl"]);
            list=[NSArray arrayWithObjects:[iscrizione objectForKey:@"title"], [iscrizione objectForKey:@"htmlUrl"], nil];  
            [sub addObject:list];
           
        }

But when I try to add list to the NSMutableArray the program crashes. Why?
How can I insert `[iscrizione objectForKey:@"title"]` and `[iscrizione objectForKey:@"htmlUrl"]`
in a data structure? 