title: what could be wrong in this batch file
body: <p>I'm trying to let the user enter numbers and if they miss one I want the program to drop an error message. However If not Defined doesn't work. </p>
  
  <pre><code>set /p aa=a11: 
  set /p ba=a12: 
  set /p ba=a12: 
  set /p ab=a21: 
  set /P bb=a22: 
  cls
  echo antra matrica
  echo.
  set /p qq=b11: 
  set /p wq=b12: 
  set /p qw=b21: 
  set /P ww=b22: 
  for %%A IN (%aa%, %ba%, %ab%, %bb%, %qq%, %wq%, %qw%, %ww%) DO IF [%%A]==[] goto error
  </code></pre>
  
  <p>It ignores the for command. What could i do to make it work when all the variables are enterd blank? </p>