function s = num2str(x, f)

%NUM2STR Convert numbers to a string.

%   T = NUM2STR(X) converts the matrix X into a string representation T

%   with about 4 digits and an exponent if required.  This is useful for

%   labeling plots with the TITLE, XLABEL, YLABEL, and TEXT commands.

%

%   T = NUM2STR(X,N) converts the matrix X into a string representation

%   with a maximum N digits of precision.  The default number of digits is

%   based on the magnitude of the elements of X.

%

%   T = NUM2STR(X,FORMAT) uses the format string FORMAT (see SPRINTF for

%   details).

%

%   Example 1:

%       num2str(randn(2,2),3) produces a string matrix such as

%

%        1.44    -0.755

%       0.325      1.37

%

%   Example 2:

%       num2str(rand(2,3) * 9999, '%10.5e\n') produces a string matrix

%       such as

%

%       8.14642e+03

%       1.26974e+03

%       6.32296e+03

%       9.05701e+03

%       9.13285e+03

%       9.75307e+02

%

%   See also INT2STR, SPRINTF, FPRINTF, MAT2STR.

%   Copyright 1984-2012 The MathWorks, Inc.

%------------------------------------------------------------------------------

    narginchk(1,2); 

    if ischar(x) 

        s = x;

        return;

    end

    if isempty(x) 

        s = '';

        return

    end

    if isfloat(x) 

        x = 0+x;  % Remove negative zero 

    end 

    if issparse(x) 

        x = full(x);

    end

    intFieldExtra = 1; 

    maxFieldWidth = 12; 

    floatWidthOffset = 4; 

    forceWidth = 0; 

    padColumnsWithSpace = true; 

    % Compose sprintf format string of numeric array.

    if nargin < 2 

        % To get the width of the elements in the output string

        widthCopy = x; 

        % replace Inf and NaN with a number of equivalent length (3 digits) for width

        % calcultion

        if isfloat(x) 

            widthCopy(~isfinite(widthCopy)) = 314; %This could be any 3 digit number 

        end 

        xmax = double(max(abs(widthCopy(:)))); 

        if isequaln(x, fix(x)) && (isinteger(x) || eps(xmax) <= 1) 

            if isreal(x)

                s = int2str(x); % Enhance the performance

                return;

            end         

            d = min(maxFieldWidth, floor(log10(xmax)) + 1);

            forceWidth = d+intFieldExtra;

            f = '%d';

        else 

            % The precision is unspecified; the numeric array contains floating point

            % numbers.

            if xmax == 0 

                d = 1;

            else 

                d = min(maxFieldWidth, max(1, floor(log10(xmax))+1))+floatWidthOffset; 

            end 

            [s, forceWidth, f] = handleNumericPrecision(x, d); 

            if ~isempty(s) 

                return; 

            end

        end

    elseif isnumeric(f) 

        f = round(real(f));

        [s, forceWidth, f] = handleNumericPrecision(x, f);

        if ~isempty(s)

            return;

        end

    elseif ischar(f) 

        % Precision is specified as an ANSI C print format string.

        % Explicit format strings should be explicitly padded

        padColumnsWithSpace = false; 

        % Validate format string

        k = strfind(f,'%'); 

        if isempty(k) 

            error(message('MATLAB:num2str:fmtInvalid', f));

        end

    else

        error(message('MATLAB:num2str:invalidSecondArgument'))        

    end

    %-------------------------------------------------------------------------------

    % Print numeric array as a string image of itself.

    if isreal(x) 

        [raw, isLeft] = cellPrintf(f, x, false); 

        [m,n] = size(raw); 

        cols = cell(1,n); 

        widths = zeros(1,n); 

        for j = 1:n 

            if isLeft 

                cols{j} = char(raw(:,j));

            else 

                cols{j} = strvrcat(raw(:,j)); 

            end 

            widths(j) = size(cols{j}, 2); 

        end 

    else

        forceWidth = 2*forceWidth + 2;

        raw = cellPrintf(f, real(x), false);

        imagRaw = cellPrintf(f, imag(x), true);

        [m,n] = size(raw);

        cols = cell(1,n);

        widths = zeros(1,n);

        for j = 1:n

            cols{j} = [strvrcat(raw(:,j)) char(imagRaw(:,j))];

            widths(j) = size(cols{j}, 2);

        end

    end

    maxWidth = max([widths forceWidth]); 

    padWidths = maxWidth - widths; 

    padIndex = find(padWidths, 1); 

    while ~isempty(padIndex) 

        padWidth = padWidths(padIndex);

        padCols = (padWidths==padWidth);

        padWidths(padCols) = 0;

        spaceCols = char(ones(m,padWidth)*' ');

        cols(padCols) = strcat({spaceCols}, cols(padCols));

        padIndex = find(padWidths, 1);

    end

    if padColumnsWithSpace 

        spaceCols = char(ones(m,1)*' ');

        cols = strcat(cols, {spaceCols});

    end

    s = strtrim([cols{:}]); 

end