Poission distribrtion with Function subprogram

Find the poission distribution with function subprogram for the values of x which is given below

  X

  0

  1

  2

  3

  4

  5

  6

  7

  8

  9

  10

Solution:  

        Function fact(N)

        INTEGER FACT

        FACT=1

        IF(N.EQ.0) RETURN

        DO I=1,N

        FACT=FACT*I

        ENDDO

        RETURN

        END

        INTEGER FACT

        REAL K1,K2,K3

        SUM=0.

        WRITE(*,*) 'ENTER THE VALUE OF X'

        READ(*,*) N

        WRITE(*,*)'ENTER THE VALUE OF LAMDA'

        READ(*,*) U

        DO J=0,N

        K1=EXP(-U)

        K2=U**J

        K3=FACT(J)

        PO=SUM+(K1*K2/K3)

         ENDDO

        WRITE(*,*) PO

        STOP

        END

Hints:

    Here we put N = 11 because we see in the total number of  observation of x is 11.