Is it mandatory to show intraday share trading losses?

If salaried person has a taxable income and Intraday trading loss of rs.40,000 and he/she does not want to carry forward the Intraday trading losses, is it mandatory for the salaried person to show losses. What happens if salaried person shows only salary income and pay taxes and ignores the Intraday trading losses while filing the taxes, will he/she be penalised by IT Dept?