ceph/src/boost/libs/format/example/sample_formats.cpp

   1 // ----------------------------------------------------------------------------
   2 // sample_formats.cpp :  example of basic usage of format
   3 // ----------------------------------------------------------------------------
   4
   5 //  Copyright Samuel Krempp 2003. Use, modification, and distribution are
   6 //  subject to the Boost Software License, Version 1.0. (See accompanying
   7 //  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   8
   9 //  See http://www.boost.org/libs/format for library home page
  10 // ----------------------------------------------------------------------------
  11
  12 #include <iostream>
  13 #include <iomanip>
  14 #include <cassert>
  15
  16 #include "boost/format.hpp"
  17
  18 // 2 custom namespaces, to bring in a few useful names :
  19
  20 namespace MyNS_ForOutput {
  21   using std::cout; using std::cerr;
  22   using std::string;
  23   using std::endl; using std::flush;
  24
  25   using boost::format;
  26   using boost::io::group;
  27 }
  28
  29 namespace MyNS_Manips {
  30   using std::setfill;
  31   using std::setw;
  32   using std::hex ;
  33   using std::dec ;
  34 // gcc-2.95 doesnt define the next ones
  35 //  using std::showbase ;
  36 //  using std::left ;
  37 //  using std::right ;
  38 //  using std::internal ;
  39 }
  40
  41 int main(){
  42     using namespace MyNS_ForOutput;
  43     using namespace MyNS_Manips;
  44
  45     std::cout << format("%|1$1| %|2$3|") % "Hello" % 3 << std::endl;
  46
  47     // Reordering :
  48     cout << format("%1% %2% %3% %2% %1% \n") % "o" % "oo" % "O"; // 'simple' style.
  49     //          prints  "o oo O oo o \n"
  50     cout << format("(x,y) = (%1$+5d,%2$+5d) \n") % -23 % 35;     // Posix-Printf style
  51
  52
  53     // No reordering :
  54     cout << format("writing %s,  x=%s : %d-th step \n") % "toto" % 40.23 % 50;
  55     //          prints  "writing toto,  x=40.23 : 50-th step \n"
  56
  57     cout << format("(x,y) = (%+5d,%+5d) \n") % -23 % 35;
  58     cout << format("(x,y) = (%|+5|,%|+5|) \n") % -23 % 35;
  59     cout << format("(x,y) = (%|1$+5|,%|2$+5|) \n") % -23 % 35;
  60     //   all those are the same,  it prints  "(x,y) = (  -23,  +35) \n"
  61
  62
  63
  64     // Using manipulators, via 'group' :
  65     cout << format("%2% %1% %2%\n")  % 1   % group(setfill('X'), hex, setw(4), 16+3) ;
  66     // prints "XX13 1 XX13\n"
  67
  68
  69     // printf directives's type-flag can be used to pass formatting options :
  70     cout <<  format("_%1$4d_ is : _%1$#4x_, _%1$#4o_, and _%1$s_ by default\n")  % 18;
  71     //          prints  "_  18_ is : _0x12_, _ 022_, and _18_ by default\n"
  72
  73     // Taking the string value :
  74     std::string s;
  75     s= str( format(" %d %d ") % 11 % 22 );
  76     assert( s == " 11 22 ");
  77
  78
  79     // -----------------------------------------------
  80     //  %% prints '%'
  81
  82     cout << format("%%##%#x ") % 20 << endl;
  83     //          prints  "%##0x14 "
  84
  85
  86     // -----------------------------------------------
  87     //    Enforcing the right number of arguments
  88
  89     // Too much arguments will throw an exception when feeding the unwanted argument :
  90     try {
  91       format(" %1% %1% ") % 101 % 102;
  92       // the format-string refers to ONE argument, twice. not 2 arguments.
  93       // thus giving 2 arguments is an error
  94     }
  95     catch (boost::io::too_many_args& exc) {
  96       cerr <<  exc.what() << "\n\t\t***Dont worry, that was planned\n";
  97     }
  98
  99
 100     // Too few arguments when requesting the result will also throw an exception :
 101     try {
 102       cerr << format(" %|3$| ") % 101;
 103       // even if %1$ and %2$ are not used, you should have given 3 arguments
 104     }
 105     catch (boost::io::too_few_args& exc) {
 106       cerr <<  exc.what() << "\n\t\t***Dont worry, that was planned\n";
 107     }
 108
 109
 110     cerr << "\n\nEverything went OK, exiting. \n";
 111     return 0;
 112 }