forloop and table in latex

Question

Hi,

Here is the latex code for my table:

  \begin{table}{| c || c | c | c || c | c | c | }  
  \caption{Examples of the concepts. \label{tab:conceptsimgs}}\\   
  \hline  
  \backslashbox{Concept}{Class} &\multicolumn{3}{|c||}{Negative Class} & \multicolumn{3}{|c|}{Positive Class}  \\  
  \hline  

  \forloop{themenumber}{1}{\value{themenumber} < 4}{  
        %\hline   
        \arabic{themenumber}  
        \forloop{classnumber}{0}{\value{classnumber} < 2}{  
            \forloop{imagenumber}{1}{\value{imagenumber} < 4}{  
                & 0  
            }  
        }  
        \\  
        \hline  
  }  

  \end{table}

Something is wrong in the result however. There is some extra thing at the end of the table, as shown in this image. How can I fix it?

Thanks and regards!