vim - how can I recover a modified file in linux -

i had created file filedetails.cpp. after editing file, got error :

**memory full. unable edit file** 

then quit(q) , re-open again see file empty. there 4 more files creates :

filedetails.cpp~ filedetails.cpw~ filedetails.cpx~ filedetails.cpy~ filedetails.cpz~ 

i dont understand has happened , how can recover.

the files ~ ending backup files. can inspect them in vim (or in shell via cat), , creation dates; if 1 of them complete, recover copying original file (cp filedetails.cpz~ filedetails.cpp in shell, or :saveas filedetails.cpp in vim).