/**
 * @author Jam Jenkins
 */
public class GroupCheck
{

    /**Finds the location of unmatched grouping characters.
     * The grouping characters are: (), {}, <>, [].
     * 
     * All grouping characters must be used in pairs and cannot
     * be interlaced.  For example, the code
     * <pre>[html]{a href="works.html"}</pre>
     * is valid, but
     * <pre>[html{]a href="works.html"}</pre>
     * is not valid at position 11 because the ] is
     * trying to close the {
     * 
     * Hint: use a stack.
     * @param code a sequence of characters
     * @return the position of an error, or -1 if there is
     * no error
     */
    public int getGroupingError(String code)
    {
        return -1;
    }
    
    public static void main(String[] args)
    {
        GroupCheck check=new GroupCheck();
        String[] code={"<pre>[html]{a href=\"works.html\"}</pre>",
                "<pre>[html{]a href=\"works.html\"}</pre>"};
        int result;
        for(int i=0; i<code.length; i++)
        {
            result=check.getGroupingError(code[i]);
            if(result<0)
                System.out.println(code[i]+" is correct");
            else
                System.out.println(code[i]+" has an error at "+result);
        }
    }
}