function [ ex ] = p02_parameters ( ex_user )

%*****************************************************************************80
%
%% p02_parameters() returns parameters for disk integrand problem 2.
%
%  Discussion:
%
%    If input values are specified, this resets the default parameters.
%    Otherwise, the output will be the current defaults.
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    11 October 2022
%
%  Author:
%
%    John Burkardt
%
%  Input:
%
%    integer ex_user: a new value for the exponent.
%
%  Output:
%
%    integer ex: the exponent.
%
  persistent ex_default;
%
%  Initialize defaults.
%
  if ( isempty ( ex_default ) )
    ex_default = 0;
  end
%
%  Update defaults if input was supplied.
%
  if ( 1 <= nargin )
    ex_default = ex_user;
  end
%
%  Return values.
%
  ex = ex_default;

  return
end

