Table layout using std::cout

How do I format my output in C++ streams to print fixed width left-aligned tables? Something like

printf("%-14.3f%-14.3f\n", 12345.12345, 12345.12345);

poducing

12345.123     12345.123

From stackoverflow

• std::cout << std::setiosflags(std::ios::fixed)
            << std::setprecision(3)
            << std::setw(18)
            << std::left
            << 12345.123;
  

• Include the standard header <iomanip> and go crazy. Specifically, the setw manipulator sets the output width. setfill sets the filling character.

  Anonymous : +1 for literally going crazy.

• You want to use stream manipulators:

  http://www.deitel.com/articles/cplusplus_tutorials/20060218/index.html

• You may also consider more friendly functionality provided by one of these:

  • Boost.Format (powerful, but very heavy, more time and memory allocations than other mentioned)
  • Loki.SafeFormat
  • FastFormat (relatively new, but blazing fast library, also type-safe unlike the others)

  Writing from memory, but should be something along these lines:

  // Dumb streams:
  printf("%-14.3f%-14.3f\n", 12345.12345, 12345.12345);
  
  // For IOStreams you've got example in the other answers
  
  // Boost Format supports various flavours of formatting, for example:
  std::cout << boost::format("%-14.3f%-14.3f\n") % a % b;
  std::cout << boost::format("%1$-14.3f%2$-14.3f\n") % a % b;
  // To gain somewhat on the performance you can store the formatters:
  const boost::format foo("%1$-14.3f%2$-14.3f\n");
  std::cout << boost::format(foo) % a % b;
  
  // For the Loki::Printf it's also similar:
  Loki::Printf("%-14.3f%-14.3f\n")(a)(b);
  
  // And finally FastFormat.Format (don't know the syntax for decimal places)
  fastformat::fmtln(std::cout, "{0,14,,<}{1,14,,>}", a, b);
  

  Also, if you plan to stick with any of these formatting libraries, examine thoroughly their limitations in context of expressibility, portability (and other library dependency), efficiency, support of internationalisation, type-safety, etc.

  jwfearn : could you add links?

  Anonymous : Links now, examples tomorrow afternoon (GMT time)

• Thanks, <iomanip> works. I also found Boost::Format, which seams to be a pretty much printf like library for string formating.

  Anonymous : Be aware of the boost::format cost though...