what is GDP and GNP?????

[Cancerian]

Asslam o alaekum to all brothers

I have a confusion about Gross dosmestic product (GDP). According to book of PBP
GDP=C+G+I+(X-M)

(X-M) means export surplus and according to PBP it is included in GDP.

i have consulted Abdul Haleem Khawja and M. Saeed Nasir and also Habibi ullah waseer. According to them this is equation of GNP..

Please anyone clear me about this

i shall be very thankful to you.

regards