Write structure array into Excel sheet

% usage: xlscell=WriteXlsFromStruct(DataStruct, outXlsName, sheet, ifOvewriteExist);
% This function writes a 1x1 structure array into Excel file.
% Each field in the input structure containes the data of a column in the output Excel sheet.
% See the sample 'xlsStruct.mat' for the format of the input structure array.
% The data struct conforms to the output struct generated by 'xls2struct.m'.
% 'ifOvewriteExist': Whether or not overwrite existing output Excel file.
% See also 'xls2struct.m'