Can i claim hra while returning the file?

you can show the all month rent slip to your current employer and he can consider the all. If he is not accepting then in that case you can claim it at the time of filing ITR. and if more tds deducted then you can get refund accordingly.

You are eligible to claim the exemption on the HRA earned by you from your previous employer provided you must have enter the correct information regarding the HRA recd and the Rent paid for the earlier 6 months. In your return for the concern period , your salary income is computed fram as earned from 2 employers and various related exemptions are calculated separately for each employment. Exemption on HRA  is calculated on a monthly basis so no matter whether you have changed your current employer or not.