title: Integer summing blues, short += short problem
body: <p>Program in C#:</p>
  
  <pre><code>short a, b;
  a = 10;
  b = 10;
  a = a + b; // Error : Cannot implicitly convert type 'int' to 'short'.
  
  // we can also write this code by using Arithmetic Assignment Operator as given below
  
  a += b; // But this is running successfully, why?
  
  Console.Write(a);
  </code></pre>