title: Full precision display of floating point numbers in C++?
body: <p>I have read several topics about the display of floating point numbers display in C++ and I couldn't find a satisfying answer. </p>
  
  <p><em>My question is:</em> <strong>how to display all the significant digits of a floating point numbers in C++ in a scientific format (mantissa/exponent) ?</strong></p>
  
  <p>The problem is that all numbers do not have the same number of significant digits in base 10. </p>
  
  <p>For example a <code>double</code> has <strong>15 to 17</strong> significant decimal digits precision, but <code>std::numeric_limits&lt;double&gt;::digits10</code> returns 15 and consequently, for some numbers I will loose 2 extra decimal digits of precision.</p>