! This is a function. 
! We probably have to declare this before the main program.
function foo(x) result(y)
    integer, intent(in)  :: x
    integer :: y
    y = x + 1
end function

! This is the main program.
program MAIN
    ! let's try to call a function.
    integer :: foo  ! We have to declare the return type of the function.
    character(len = 4) :: str
    integer :: z

    str = 'Bond'
    print *, str
    z = foo(41)
    print *,z
    print *,foo(007)
    stop
end program