how to store NSString in Stack - ios

Question

I create stack class in my program that I want store NSString value in that.
this is stack class :
#interface Stack : NSObject
- (void)push:(id)obj;
- (id)pop;
- (BOOL)isEmpty;
#end
#implementation Stack
{
NSMutableArray *stack;
}
- (id)init
{
self = [super init];
if(self!= nil){
stack = [[NSMutableArray alloc] init];
}
return self;
}
- (void)push:(id)obj
{
[stack addObject:obj];
}
- (id)pop
{
id lastobj = [stack lastObject];
[stack removeLastObject];
return lastobj;
}
- (BOOL)isEmpty
{
return stack.count == 0;
}
#end
also I have another class with name : TableViewController
I want when to click on cell in TableViewController store cell's id that receive from URL
this is my code:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// I want that xCode value with xCode2 value push in stack
NSLog(#"Row in Tab : %d",indexPath.row);
if ([Folder containsObject:[All objectAtIndex:indexPath.row]]) {
NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:#"http://192.168.1.%d/mamal/filemanager.php?dir=%#&folder=%d&id",IP,xCode,indexPath.row]];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
NSURLResponse *response = nil;
NSError *err = nil;
NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&err];
NSString *responseString = [[NSString alloc] initWithBytes:[data bytes] length:[data length] encoding:NSUTF8StringEncoding];
xCode2 = responseString; //this is new cell's id.I want to push this value in stack
NSLog(#"xcode : %#", xCode2);
[self performSegueWithIdentifier:#"segue4" sender:self];
}
else
{
[self performSegueWithIdentifier:#"segue3" sender:self];
}
}
in top code I want when to click on cell push two value in stack (xCode & xCode2) but I dont know about to use of stack.

Answer 1

you need a variable that holds your stack.. i'd make it a member var:
#implementation TableViewController {
Stack *_stack;
}
...
then when the cell is clicked, push the value
...
if(!_stack)
_stack = [[Stack alloc] init];
[_stack push:xcode2];
...

Answer 2

In addition to what Daij-Djan has suggested, do the following:
#interface Stack : NSMutableArray
- (void)push:(id)obj;
- (id)pop;
- (BOOL)isEmpty;
#end
#implementation Stack
- (id)init
{
self = [super init];
if(self!= nil){
// Perform any initialization here. If you don't then there is no point in implementing init at all.
}
return self;
}
- (void)push:(id)obj
{
[self addObject:obj];
}
- (id)pop
{
id lastobj = [self lastObject];
[self removeLastObject];
return lastobj;
}
- (BOOL)isEmpty
{
return [self count] == 0;
}
#end