title: Digit limitation from decimal point in C++
body: <p>I'm new to C++. I have a double variable <code>double a=0.1239857</code> and I want to limit variable <code>a</code> from decimal point two digits. So <code>a</code> will be <code>0.12</code>. I know  C++ have functions that return largest or smallest integer that is greater or lower than <code>a</code> like ceil or floor.</p>
  <p>Is there a function that implements digit limitation of floating-point variable? Or How can I change precision of the <code>a</code> variable?</p>