function varargout = setdiff(varargin)

%SETDIFF Set difference.

%   C = SETDIFF(A,B) for vectors A and B, returns the values in A that 

%   are not in B with no repetitions. C will be sorted.

%

%   C = SETDIFF(A,B,'rows') for matrices A and B with the same number of

%   columns, returns the rows from A that are not in B. The rows of the

%   matrix C will be in sorted order.

%

%   [C,IA] = SETDIFF(A,B) also returns an index vector IA such that

%   C = A(IA). If there are repeated values in A that are not in B, then

%   the index of the first occurrence of each repeated value is returned.

%

%   [C,IA] = SETDIFF(A,B,'rows') also returns an index vector IA such that

%   C = A(IA,:).

%

%   [C,IA] = SETDIFF(A,B,'stable') for arrays A and B, returns the values

%   of C in the order that they appear in A.

%   [C,IA] = SETDIFF(A,B,'sorted') returns the values of C in sorted order.

%   If A is a row vector, then C will be a row vector as well, otherwise C

%   will be a column vector. IA is a column vector. If there are repeated

%   values in A that are not in B, then the index of the first occurrence of

%   each repeated value is returned.

%

%   [C,IA] = SETDIFF(A,B,'rows','stable') returns the rows of C in the

%   same order that they appear in A.

%   [C,IA] = SETDIFF(A,B,'rows','sorted') returns the rows of C in sorted

%   order.

%

%   The behavior of SETDIFF has changed.  This includes:

%     -	occurrence of indices in IA switched from last to first

%     -	orientation of vector C

%     -	IA will always be a column index vector

%     -	tighter restrictions on combinations of classes

% 

%   If this change in behavior has adversely affected your code, you may 

%   preserve the previous behavior with:

% 

%      [C,IA] = SETDIFF(A,B,'legacy')

%      [C,IA] = SETDIFF(A,B,'rows','legacy')

%

%   Examples:

%

%      a = [9 9 9 9 9 9 8 8 8 8 7 7 7 6 6 6 5 5 4 2 1]

%      b = [1 1 1 3 3 3 3 3 4 4 4 4 4 10 10 10]

%

%      [c1,ia1] = setdiff(a,b)

%      % returns

%      c1 = [2 5 6 7 8 9]

%      ia1 = [20 17 14 11 7 1]'

%

%      [c2,ia2] = setdiff(a,b,'stable')

%      % returns

%      c2 = [9 8 7 6 5 2]

%      ia2 = [1 7 11 14 17 20]'

%

%      c = setdiff([1 NaN 2 3],[3 4 NaN 1])

%      % NaNs compare as not equal, so this returns

%      c = [2 NaN]

%

%   Class support for inputs A and B, where A and B must be of the same

%   class unless stated otherwise:

%      - logical, char, all numeric classes (may combine with double arrays)

%      - cell arrays of strings (may combine with char arrays)

%      -- 'rows' option is not supported for cell arrays

%      - objects with methods SORT (SORTROWS for the 'rows' option), EQ and NE

%      -- including heterogeneous arrays derived from the same root class

%

%   See also UNIQUE, UNION, INTERSECT, SETXOR, ISMEMBER, SORT, SORTROWS.

%   Copyright 1984-2017 The MathWorks, Inc.

% Determine the number of outputs requested.

if nargout == 0 

    nlhs = 1;

else 

    nlhs = nargout; 

end 

narginchk(2,4); 

% Convert string flags to char flags to dispatch to the right method

if (nargin == 3) && isstring(varargin{3}) 

    varargin{3} = convertFlag(varargin{3});

    [varargout{1:nlhs}] = setdiff(varargin{:});

    return;

end

if (nargin == 4) && (isstring(varargin{3}) || isstring(varargin{4})) 

    if isstring(varargin{3})

        varargin{3} = convertFlag(varargin{3});

    end

    if isstring(varargin{4})

        varargin{4} = convertFlag(varargin{4});

    end

    [varargout{1:nlhs}] = setdiff(varargin{:});

    return;

end

if isstring(varargin{1}) || isstring(varargin{2}) 

    if ~ischar(varargin{1}) && ~iscellstr(varargin{1}) && ~isstring(varargin{1})

        firstInput = getString(message('MATLAB:string:FirstInput'));

        error(message('MATLAB:string:MustBeCharCellArrayOrString', firstInput));

    elseif ~ischar(varargin{2}) && ~iscellstr(varargin{2}) && ~isstring(varargin{2})

        secondInput = getString(message('MATLAB:string:SecondInput'));

        error(message('MATLAB:string:MustBeCharCellArrayOrString', secondInput));

    end

    varargin{1} = string(varargin{1});

    varargin{2} = string(varargin{2});

end

nrhs = nargin; 

if nrhs == 2 

    [varargout{1:nlhs}] = setdiffR2012a(varargin{:}); 

else

    % acceptable combinations, with optional inputs denoted in []

    % setdiff(A,B, ['rows'], ['legacy'/'R2012a']),

    % setdiff(A,B, ['rows'], ['sorted'/'stable']),

    % where the position of 'rows' and 'sorted'/'stable' may be reversed

    nflagvals = 5;

    flagvals = ["rows" "sorted" "stable" "legacy" "R2012a"];

    % When a flag is found, note the index into varargin where it was found

    flaginds = zeros(1,nflagvals);

    for i = 3:nrhs

        flag = varargin{i};

        assert(~isstring(flag));

        if ~ischar(flag)

            error(message('MATLAB:SETDIFF:UnknownInput'));

        end

        foundflag = startsWith(flagvals,flag,'IgnoreCase',true);

        if sum(foundflag) ~= 1

            error(message('MATLAB:SETDIFF:UnknownFlag',flag));

        end

        % Only 1 occurrence of each allowed flag value

        if flaginds(foundflag)

            error(message('MATLAB:SETDIFF:RepeatedFlag',flag));

        end

        flaginds(foundflag) = i;

    end

    % Only 1 of each of the paired flags

    if flaginds(2) && flaginds(3)

        error(message('MATLAB:SETDIFF:SetOrderConflict'))

    end

    if flaginds(4) && flaginds(5)

        error(message('MATLAB:SETDIFF:BehaviorConflict'))

    end

    % 'legacy' and 'R2012a' flags must be trailing

    if flaginds(4) && flaginds(4)~=nrhs

        error(message('MATLAB:SETDIFF:LegacyTrailing'))

    end

    if flaginds(5) && flaginds(5)~=nrhs

        error(message('MATLAB:SETDIFF:R2012aTrailing'))

    end

    if flaginds(2) || flaginds(3) % 'stable'/'sorted' specified

        if flaginds(4) || flaginds(5) % does not combine with 'legacy'/'R2012a'

            error(message('MATLAB:SETDIFF:SetOrderBehavior'))

        end

        [varargout{1:nlhs}] = setdiffR2012a(varargin{1:2},logical(flaginds(1:3)));

    elseif flaginds(5) % trailing 'R2012a' specified

        [varargout{1:nlhs}] = setdiffR2012a(varargin{1:2},logical(flaginds(1:3)));

    elseif flaginds(4) % trailing 'legacy' specified

        [varargout{1:nlhs}] = setdifflegacy(varargin{1:2},logical(flaginds(1)));

    else % 'R2012a' (default behavior)

        [varargout{1:nlhs}] = setdiffR2012a(varargin{1:2},logical(flaginds(1:3)));

    end

end 

end