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