doc: Ensure documentation lists output argument when it exists for all m-files. For new users of Octave it is best to show explicit calling forms in the documentation and to show a return argument when it exists. * bp-table.cc, shift.m, accumarray.m, accumdim.m, bincoeff.m, bitcmp.m, bitget.m, bitset.m, blkdiag.m, celldisp.m, cplxpair.m, dblquad.m, flip.m, fliplr.m, flipud.m, idivide.m, int2str.m, interpft.m, logspace.m, num2str.m, polyarea.m, postpad.m, prepad.m, randi.m, repmat.m, rng.m, rot90.m, rotdim.m, structfun.m, triplequad.m, uibuttongroup.m, uicontrol.m, uipanel.m, uipushtool.m, uitoggletool.m, uitoolbar.m, waitforbuttonpress.m, help.m, __additional_help_message__.m, hsv.m, im2double.m, im2frame.m, javachk.m, usejava.m, argnames.m, char.m, formula.m, inline.m, __vectorize__.m, findstr.m, flipdim.m, strmatch.m, vectorize.m, commutation_matrix.m, cond.m, cross.m, duplication_matrix.m, expm.m, orth.m, rank.m, rref.m, trace.m, vech.m, cast.m, compare_versions.m, delete.m, dir.m, fileattrib.m, grabcode.m, gunzip.m, inputname.m, license.m, list_primes.m, ls.m, mexext.m, movefile.m, namelengthmax.m, nargoutchk.m, nthargout.m, substruct.m, swapbytes.m, ver.m, verLessThan.m, what.m, fminunc.m, fsolve.m, fzero.m, optimget.m, __fdjac__.m, matlabroot.m, savepath.m, campos.m, camroll.m, camtarget.m, camup.m, camva.m, camzoom.m, clabel.m, diffuse.m, legend.m, orient.m, rticks.m, specular.m, thetaticks.m, xlim.m, xtickangle.m, xticklabels.m, xticks.m, ylim.m, ytickangle.m, yticklabels.m, yticks.m, zlim.m, ztickangle.m, zticklabels.m, zticks.m, ellipsoid.m, isocolors.m, isonormals.m, stairs.m, surfnorm.m, __actual_axis_position__.m, __pltopt__.m, close.m, graphics_toolkit.m, pan.m, print.m, printd.m, __ghostscript__.m, __gnuplot_print__.m, __opengl_print__.m, rotate3d.m, subplot.m, zoom.m, compan.m, conv.m, poly.m, polyaffine.m, polyder.m, polyint.m, polyout.m, polyreduce.m, polyvalm.m, roots.m, prefdir.m, prefsfile.m, profexplore.m, profexport.m, profshow.m, powerset.m, unique.m, arch_rnd.m, arma_rnd.m, autoreg_matrix.m, bartlett.m, blackman.m, detrend.m, durbinlevinson.m, fftconv.m, fftfilt.m, fftshift.m, fractdiff.m, hamming.m, hanning.m, hurst.m, ifftshift.m, rectangle_lw.m, rectangle_sw.m, triangle_lw.m, sinc.m, sinetone.m, sinewave.m, spectral_adf.m, spectral_xdf.m, spencer.m, ilu.m, __sprand__.m, sprand.m, sprandn.m, sprandsym.m, treelayout.m, beta.m, betainc.m, betaincinv.m, betaln.m, cosint.m, expint.m, factorial.m, gammainc.m, gammaincinv.m, lcm.m, nthroot.m, perms.m, reallog.m, realpow.m, realsqrt.m, sinint.m, hadamard.m, hankel.m, hilb.m, invhilb.m, magic.m, pascal.m, rosser.m, toeplitz.m, vander.m, wilkinson.m, center.m, corr.m, cov.m, discrete_cdf.m, discrete_inv.m, discrete_pdf.m, discrete_rnd.m, empirical_cdf.m, empirical_inv.m, empirical_pdf.m, empirical_rnd.m, kendall.m, kurtosis.m, mad.m, mean.m, meansq.m, median.m, mode.m, moment.m, range.m, ranks.m, run_count.m, skewness.m, spearman.m, statistics.m, std.m, base2dec.m, bin2dec.m, blanks.m, cstrcat.m, deblank.m, dec2base.m, dec2bin.m, dec2hex.m, hex2dec.m, index.m, regexptranslate.m, rindex.m, strcat.m, strjust.m, strtrim.m, strtrunc.m, substr.m, untabify.m, __have_feature__.m, __prog_output_assert__.m, __run_test_suite__.m, example.m, fail.m, asctime.m, calendar.m, ctime.m, date.m, etime.m: Add return arguments to @deftypefn macros where they were missing. Rename variables in functions (particularly generic "retval") to match documentation. Rename some return variables for (hopefully) better clarity (e.g., 'ax' to 'hax' to indicate it is a graphics handle to an axes object).

########################################################################
##
## Copyright (C) 1993-2022 The Octave Project Developers
##
## See the file COPYRIGHT.md in the top-level directory of this
## distribution or <https://octave.org/copyright/>.
##
## This file is part of Octave.
##
## Octave is free software: you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## Octave is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING.  If not, see
## <https://www.gnu.org/licenses/>.
##
########################################################################

## -*- texinfo -*-
## @deftypefn {} {@var{str} =} int2str (@var{n})
## Convert an integer (or array of integers) to a string (or a character
## array).
##
## @example
## @group
## int2str (123)
##   @result{} 123
##
## s = int2str ([1, 2, 3; 4, 5, 6])
##   @result{} s =
##         1  2  3
##         4  5  6
##
## whos s
##   @result{} Variables in the current scope:
##         Attr Name        Size                     Bytes  Class
##         ==== ====        ====                     =====  =====
##              s           2x7                         14  char
##      Total is 14 elements using 14 bytes
## @end group
## @end example
##
## This function is not very flexible.  For better control over the
## results, use @code{sprintf} (@pxref{Formatted Output}).
##
## Programming Notes:
##
## Non-integers are rounded to integers before display.  Only the real part
## of complex numbers is displayed.
##
## @seealso{sprintf, num2str, mat2str}
## @end deftypefn

function str = int2str (n)

  if (nargin < 1)
    print_usage ();
  elseif (! (isnumeric (n) || islogical (n) || ischar (n)))
    error ("int2str: N must be a numeric, logical, or character array");
  endif

  if (ischar (n))
    str = n;
    return;
  elseif (isempty (n))
    str = "";
    return;
  endif

  n = round (real (n));

  ## Set up a suitable format string while ignoring Inf/NaN entries
  nan_inf = ! isfinite (n(:));
  ndgt = floor (log10 (max (abs (n(! nan_inf)))));
  if (isempty (ndgt) || ndgt == -Inf)
    ndgt = 0;  # All Inf or all zero array
  endif

  ndgt += 3;
  if (any (nan_inf))
    ndgt = max (ndgt, 5);
  endif

  ## FIXME: Integers should be masked to show only 16 significant digits
  fmt = sprintf ("%%%d.0f", ndgt);

  nd = ndims (n);
  nc = columns (n) * (nd - 1);    # ND-arrays are expanded in columns
  n  = permute (n, [2, 3:nd, 1]);
  fmt = [repmat(fmt, 1, nc), "\n"];
  strtmp = sprintf (fmt, n);
  str = strtrim (char (ostrsplit (strtmp, "\n", true)));

endfunction


%!assert (int2str (123), "123")
%!assert (int2str (-123), "-123")
%!assert (int2str (1.2), "1")
%!assert (int2str (1.6), "2")
%!assert (int2str ([1, 2, 3; 4, 5, 6]), ["1  2  3";"4  5  6"])
%!assert (int2str ([]), "")

%!error <Invalid call> int2str ()
%!error <N must be a numeric> int2str ({1})