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[ooo1Adrian1ooo]

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[hamsterman]

So which one you don't know:
open a file, read some floats, square them, Open another file, write them ?

[Mathes]

ok, you may read these:

reading a file
http://cplusplus.com/reference/iostream/ifstream/

writing to a file
http://cplusplus.com/reference/iostream/ofstream/

and the filename, that is given via command line, will be stored in argv[1], if argc >= 2.