/* column to item number */
_col2itm(c)
{
        local n, ic, tc, nc;

        nc = numitems;
        tc = 0;
        for (n = 1; n < nc; n++)
        {
                ic = itemcount(n);
                if (c <= ic + tc) break;
                tc += ic;
        }
        return(n);
}