title: NScoder objective-c run time
body: <pre><code>NSCoder *coder; 
  coder=[[NSCoder alloc]init];
  [coder encodeObject:@"value" forKey:@"frame"];
  </code></pre>
  
  <h1>Error</h1>
  
  <blockquote>
    <p>Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -encodeObject:forKey: cannot be sent to an abstract object of class NSCoder: Create a concrete instance!`</p>
  </blockquote>
  
  <hr>
  
  <p>this breaks during run time.can any body help me to find it what i am doing wrong?</p>