PROGRAM Dev_stand
   IMPLICIT NONE
   REAL, ALLOCATABLE, DIMENSION(:) :: X
   INTEGER :: n_elts,  istat
   REAL :: Std_Dev
 
   WRITE(*,*) "Quanti elementi ha il vettore X?"
   READ(*,*) n_elts
   ALLOCATE(X(n_elts) ,STAT=istat)
   IF (istat .NE.0) THEN
      WRITE(*,*) "Allocazione fallita"
   ELSE
      WRITE(*,*)  "Inserisci i ",n_elts," numeri"
      READ(*,*) X
      WRITE(*,*) "Std Dev = ", Std_Dev(x,N_ELTS)
      DEALLOCATE(X)
   END IF
   STOP

END PROGRAM Dev_stand 

REAL FUNCTION Std_Dev(vect,n)
    IMPLICIT NONE
    INTEGER :: n
    REAL, DIMENSION(n) :: vect
    REAL :: mean
    mean = SUM(vect)/REAL (n)
    Std_Dev = SQRT(SUM((vect-mean)**2)/REAL(n))
END FUNCTION Std_Dev