title: Swapping two variable value without using third variable
body: <p>One of the very tricky questions asked in an interview.</p>
  
  <p>Swap the values of two variables like <code>a=10</code> and <code>b=15</code>.</p>
  
  <p>Generally to swap two variables values, we need 3rd variable like:</p>
  
  <pre><code>temp=a;
  a=b;
  b=temp;
  </code></pre>
  
  <p>Now the requirement is, swap values of two variables without using 3rd variable.</p>