function [train,test] = getdata(datafile,dataDim)
% syntax: [train,test] = getdata(datafile,dataDim)
% extract data from the database
% here, datafile should be a string, eg 'wdbc.data'
%       dataDim is a scalar, eg 30

% first check input data
if (nargin < 2) 
  error('two input arguments are required to getdata');
end
if (~ischar(datafile))
  error('first argument must be a string');
end
if (isnumeric(dataDim)&max(size(dataDim))==1)
  if (isempty(dataDim)) 
    error('second argument must be a scalar');
  elseif (dataDim <= 0) 
    error('second argument must be a positive integer');
  end
else
  error('second argument must be a positive number');
end
    
fp = fopen(datafile,'r');
samples = 0;
train = zeros(0,dataDim+1);
[id,count] = fscanf(fp,'%d,',1);
while (count == 1) 
  samples = samples + 1;
  type = fscanf(fp,'%1s',1);
  vec = fscanf(fp,',%e',dataDim);
  train = [train; abs(type) vec'];
  [id,count] = fscanf(fp,'%d,',1);
end
if (samples < 569) 
  error('Not enough samples');
end
test = train(501:samples,:);
train = train(1:500,:);
return;