title: Adding string Elements in NSArray
body: <p>I have mutable string  array named arrayout.
  It is having 3 element .Now I want to add 1 String element that array.But when I try to add,it is taking null value....Cant get what to do...Please help...</p>
  
  <p>My code is : </p>
  
  <pre><code>       NSString *ds1 = @"--";
          [arrayout arrayByAddingObject:ds1];
          NSLog(@"arrrrr '%@'",arrayout);
  </code></pre>