iPhone's UITableViewCellAccessoryCheckMark

Question

Hello everyone,

I have an issue in creating a CheckMarkAccessoryView in the UITableView.When i select a row in th table,i can get a checked mark for that row,but randomly some other rows in the table also gets the check mark.I want only that cell to get the check mark.How can i do this?I am coding for an exclusive list.The following is the code which i have used.

-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{   
    return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section 
{   
    if(tableView==tableView1)
    {
        return […arraycount1…. ];
    }
    else 
    {   
        return […arraycount2…. ];
    }
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{

    static NSString *CellIdentifier = @"Cell";

    cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) 
    { 
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
    }
    else 
    {
        UIView* subview;
        while ((subview = [[[cell contentView] subviews] lastObject]) != nil)
            [subview removeFromSuperview];
    }

    if(tableView==tableView1)
    {
            cell.textLabel.text=[array1 objectAtIndex:indexPath.row];
    }
    else                    //Tableview2
    {
            cell.textLabel.text=[array2 objectAtIndex:indexPath.row];       
    }

    cell.textLabel.font=[UIFont fontWithName:@"Georgia" size:20];
    cell.textLabel.textAlignment=UITextAlignmentLeft;
    [cell setSelectedBackgroundView:border];    
    return cell;

}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{   

        UITableViewCell *oldCell = [tableView cellForRowAtIndexPath:lastindex]; 
        if (oldCell.accessoryType == UITableViewCellAccessoryCheckmark); 
        {   
            oldCell.accessoryType = UITableViewCellAccessoryNone;   
        }

        UITableViewCell *newCell = [tableView cellForRowAtIndexPath:indexPath];     

        if (newCell.accessoryType == UITableViewCellAccessoryNone) 
        {   
            newCell.accessoryType = UITableViewCellAccessoryCheckmark;  
        }   
}

Kindly correct me where i am going wrong. Thanks in advance for all the experts.