write to a file with a variable filename

fooName.f90

program foo

    character(len=12) :: filename
    integer           :: i
    
    i = 10
    write (filename, "(A4,i0.4,A4)") "file", i,".dat"

    print*, trim(filename)

    open(1, file=filename)
!    write to the file
    close(1)

end program foo