Save data into NsuserDefault using objective C

- (IBAction)SaveUsingNsuserDefault:(id)sender

{

NSMutableArray* mutableArry   =  [[NSMutableArray alloc] init];

    NSMutableDictionary *array = [[NSMutableDictionary alloc]init];

    [array setObject:txtName.text forKey:@"name"];

    [array setObject:txtCity.text forKey:@"city"];

    [array setObject:txtPass.text forKey:@"pass"];

    

    NSMutableArray *studentArray;

    NSUserDefaults *currentDefaults = [NSUserDefaults standardUserDefaults];

    NSArray *previousSavedArray = [currentDefaults objectForKey:@"saveStudents"];

    if (previousSavedArray != nil)

        studentArray = [[NSMutableArray alloc] initWithArray:previousSavedArray];

    else

        studentArray = [[NSMutableArray alloc] init];

    

    NSMutableArray* arrStudentDetails = [currentDefaults objectForKey:@"saveStudents"];

    

    mutableArry = arrStudentDetails;

    

    if([[txtName.text checkNullFromString:txtName.text] isEqualToString:@""]|| [[txtCity.text checkNullFromString:txtCity.text] isEqualToString:@""]|| [[txtPass.text checkNullFromString:txtPass.text] isEqualToString:@""])

    {

        UIAlertView* alert = [[UIAlertView alloc]initWithTitle:@"Required" message:@"Empty Field not allowed !!" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];

        [alert show];

        

        if([mutableArry count]>0)

        {

            [self.tblEmpDetails reloadData];

        }

        return;

    }

   

        int j = [previousSavedArray count];

        for (int i = 0; j>i; i++) 

        {

            NSString* strName = [[previousSavedArray objectAtIndex:i]valueForKey:@"name"];

            if([strName isEqualToString:txtName.text])

            {

                

                UIAlertView* alert = [[UIAlertView alloc]initWithTitle:@"Exist" message:@"Record allready exist !!" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];

                [alert show];

                return;

            }

        }

    

    [studentArray addObject:array];

    [currentDefaults setObject:studentArray forKey:@"saveStudents"];

    [currentDefaults synchronize];

    

        UIAlertView* alert = [[UIAlertView alloc]initWithTitle:@"Success" message:@"Saved successfully !!" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];

        [alert show];

    

     arrStudentDetails = [currentDefaults  objectForKey:@"saveStudents"];

    mutableArry = arrStudentDetails;

    if([mutableArry count]>0)

    {

        [self.tblEmpDetails reloadData];

    }

}