| // ---------------------------------------------------------------------------- |
| // 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; |
| } |