libstdc++-v3/testsuite/27_io/basic_ostream/inserters_arithmetic/char/5.cc

   1 // 1999-11-15 Kevin Ediger  <kediger@licor.com>
   2 // test the floating point inserters (facet num_put)
   3
   4 // Copyright (C) 1999-2019 Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // You should have received a copy of the GNU General Public License along
  18 // with this library; see the file COPYING3.  If not see
  19 // <http://www.gnu.org/licenses/>.
  20
  21 #include <cmath> // for abs
  22 #include <cfloat> // for DBL_EPSILON
  23 #include <sstream>
  24 #include <limits>
  25 #include <testsuite_hooks.h>
  26
  27 void
  28 test05()
  29 {
  30   using namespace std;
  31
  32   double pi = 3.14159265358979323846;
  33   ostringstream ostr;
  34   ostr.precision(20);
  35   ostr << pi;
  36   string sval = ostr.str();
  37   istringstream istr (sval);
  38   double d;
  39   istr >> d;
  40   VERIFY( abs(pi-d)/pi < DBL_EPSILON );
  41 }
  42
  43 int
  44 main()
  45 {
  46   test05();
  47   return 0;
  48 }