function c_inc = digit_inc ( c )

% C_INC increments a digit.
%
%  Discussion:
%
%    0 goes to 1, 1 goes to 2 and so on, but 9 goes back to 0.
%
%  Modified:
%
%    14 June 2003
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, character C, a character.
%
%    Output, character C_INC, the incremented character.
%
  if ( '0' <= c & c < '9' )
    c_inc = char ( 1 + double ( c ) );
  elseif ( c == '9' )
    c_inc = '0';
  else
    c_inc = ' ';
  end