C++ alignment when printing cout <<

Question

Is there a way to align text when printing using std::cout? I'm using tabs, but when the words are too big they won't be aligned anymore.

Sales Report for September 15, 2010 Artist  Title   Price   Genre   Disc    Sale    Tax Cash Merle   Blue    12.99   Country 4%  12.47   1.01    13.48 Richard Music   8.49    Classical   8%  7.81    0.66    8.47 Paula   Shut    8.49    Classical   8%  7.81    0.72    8.49 

Answer 1

The ISO C++ standard way to do it is to #include <iomanip> and use io manipulators like std::setw. However, that said, those io manipulators are a real pain to use even for text, and are just about unusable for formatting numbers (I assume you want your dollar amounts to line up on the decimal, have the correct number of significant digits, etc.). Even for just plain text labels, the code will look something like this for the first part of your first line:

// using standard iomanip facilities cout << setw(20) << "Artist"      << setw(20) << "Title"      << setw(8) << "Price"; // ... not going to try to write the numeric formatting... 

If you are able to use the Boost libraries, run (don't walk) and use the Boost.Format library instead. It is fully compatible with the standard iostreams, and it gives you all the goodness for easy formatting with printf/Posix formatting string, but without losing any of the power and convenience of iostreams themselves. For example, the first parts of your first two lines would look something like:

// using Boost.Format cout << format("%-20s %-20s %-8s\n")  % "Artist" % "Title" % "Price"; cout << format("%-20s %-20s %8.2f\n") % "Merle" % "Blue" % 12.99;