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// ----------------------------------------------------------------------------
// sample_advanced.cc : examples of adanced usage of format
// ----------------------------------------------------------------------------
// Copyright Samuel Krempp 2003. Use, modification, and distribution are
// subject to the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
// See http://www.boost.org/libs/format for library home page
// ----------------------------------------------------------------------------
#include <iostream>
#include <iomanip>
#include "boost/format.hpp"
namespace MyNS_ForOutput {
using std::cout; using std::cerr;
using std::string;
using std::endl; using std::flush;
using boost::format;
using boost::io::group;
}
namespace MyNS_Manips {
using std::setfill;
using std::setw;
using std::hex ;
using std::dec ;
using std::showbase ;
using std::left ;
using std::right ;
using std::internal ;
}
int main(){
using namespace MyNS_ForOutput;
using namespace MyNS_Manips;
std::string s;
//------------------------------------------------------------------------
// storing the parsed format-string in a 'formatter' :
// format objects are regular objects that can be copied, assigned,
// fed arguments, dumped to a stream, re-fed arguments, etc...
// So users can use them the way they like.
format fmter("%1% %2% %3% %1% \n");
fmter % 10 % 20 % 30;
cout << fmter;
// prints "10 20 30 10 \n"
// note that once the fmter got all its arguments,
// the formatted string stays available (until next call to '%')
// The result is available via function str() or stream's << :
cout << fmter;
// prints the same string again.
// once you call operator% again, arguments are cleared inside the object
// and it is an error to ask for the conversion string before feeding all arguments :
fmter % 1001;
try { cout << fmter; }
catch (boost::io::too_few_args& exc) {
cout << exc.what() << "***Dont worry, that was planned\n";
}
// we just need to feed the last two arguments, and it will be ready for output again :
cout << fmter % 1002 % 1003;
// prints "1001 1002 1003 1001 \n"
cout << fmter % 10 % 1 % 2;
// prints "10 1 2 10 \n"
//---------------------------------------------------------------
// using format objects
// modify the formatting options for a given directive :
fmter = format("%1% %2% %3% %2% %1% \n");
fmter.modify_item(4, group(setfill('_'), hex, showbase, setw(5)) );
cout << fmter % 1 % 2 % 3;
// prints "1 2 3 __0x2 1 \n"
// bind one of the argumets :
fmter.bind_arg(1, 18);
cout << fmter % group(hex, showbase, 20) % 30; // %2 is 20, and 20 == 0x14
// prints "18 0x14 30 _0x14 18 \n"
fmter.modify_item(4, setw(0)); // cancels previous width-5
fmter.bind_arg(1, 77); // replace 18 with 77 for first argument.
cout << fmter % 10 % 20;
// prints "77 10 20 0xa 77 \n"
try
{
cout << fmter % 6 % 7 % 8; // Aye ! too many args, because arg1 is bound already
}
catch (boost::io::too_many_args& exc)
{
cout << exc.what() << "***Dont worry, that was planned\n";
}
// clear regular arguments, but not bound arguments :
fmter.clear();
cout << fmter % 2 % 3;
// prints "77 2 3 0x2 77 \n"
// clear_binds() clears both regular AND bound arguments :
fmter.clear_binds();
cout << fmter % 1 % 2 % 3;
// prints "1 2 3 0x2 1 \n"
// setting desired exceptions :
fmter.exceptions( boost::io::all_error_bits ^( boost::io::too_many_args_bit ) );
cout << fmter % 1 % 2 % 3 % 4 % 5 % 6 ;
// -----------------------------------------------------------
// misc:
// unsupported printf directives %n and asterisk-fields are purely ignored.
// do *NOT* provide an argument for them, it is an error.
cout << format("|%5d| %n") % 7 << endl;
// prints "| 7| "
cout << format("|%*.*d|") % 7 << endl;
// prints "|7|"
// truncations of strings :
cout << format("%|.2s| %|8c|.\n") % "root" % "user";
// prints "ro u.\n"
// manipulators conflicting with format-string : manipulators win.
cout << format("%2s") % group(setfill('0'), setw(6), 1) << endl;
// prints "000001"
cout << format("%2$5s %1% %2$3s\n") % 1 % group(setfill('X'), setw(4), 2) ;
// prints "XXX2 1 XXX2\n"
// width is 4, as set by manip, not the format-string.
// nesting :
cout << format("%2$014x [%1%] %2$05s\n") % (format("%05s / %s") % -18 % 7)
% group(showbase, -100);
// prints "0x0000ffffff9c [-0018 / 7] -0100\n"
cout << "\n\nEverything went OK, exiting. \n";
return 0;
}
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