title: print X number after the decimal point using the cout
body: <p>I have this code:</p>
  
  <pre><code>double a = 7.456789;
  cout.unsetf(ios::floatfield);
  cout.precision(5);
  cout &lt;&lt; a;
  </code></pre>
  
  <p>and also this one: </p>
  
  <pre><code>double a = 798456.6;
  cout.unsetf(ios::floatfield);
  cout.precision(5);
  cout &lt;&lt; a;
  </code></pre>
  
  <p>the result of the first code is: 7.4568
  Which is almost what I want (what I want to recieve is 7.4567)
  the result of the second : 7.9846e+05
  Which is not at all what I want (I want 798456.6)
  I want to print the number till 4 numbers after the decimal point</p>
  
  <p>How can I do that ?</p>