CSCE 150 Exam I 10/25/2000

Name: SS#:

(1) (30 points) Write a Fortran 90 FUNCTION which calculates N!. Call the function MyFunction. The input for the function is a positive integer N and the output is N!.

Solution:

FUNCTION MyFunction(N)

IMPLICIT NONE

INTEGER :: MyFunction, I

INTEGER, INTENT(IN) :: N

MyFunction=1

DO I=1, N

MyFunction=MyFunction*I

END DO

END FUNCTION MyFunction

(2) (45 points) Find the output of the following segments:

(a) In the following SUM is a variable of type INTEGER.

---------------------

SUM=0

DO J=1,3

SUM=SUM+J*J

END DO

PRINT *, “Sum= “, SUM

--------------------

Output: Sum= 14

(b) In the following X and Y are variables of type REAL.

-----------------

X=2.3

IF (X<1.0) THEN

Y=100*X

ELSE IF (X>2.5) THEN

Y=10*X

ELSE

Y=2*X

END IF

PRINT *, “The value of Y is: “, Y

------------------

Output: The value of Y is: 4.6

(c) Find the value of MyProd(3).

----------------

FUNCTION MyProd(K)

IMPLICIT NONE

INTEGER, INTENT(IN) :: K

INTEGER :: MyProd, I

MyProd=1

DO I=1, K

MyProd=MyProd*2

END DO

END FUNCTION MyProd

------------------

MyProd(3)=8

(3) (25 points) Find all the errors in the following program:

PROGRAM MyProgram

IMPLICIT NoNe

INTEGER : L, M, N !Error here; should be INTEGER :: L, M, N

N=MOD(7:N) !Error here for two reasons.

N=2

IF (N=3) THEN !Error here; should be (N==3)

PRINT *, “There is an error in this statement”

END IF

M=My_Function(2)

CONTAINS

FUNCTION My_Function(R)

INTEGER, INTENT(IN) :: R

!Error here; should have INTEGER :: My_Function

IF (R<2) THEN

My_Function=R

ELSE

R=2*R !Error here; cannot change the value of R.

My_Function=R

END IF

END My_Function !Error; should be END FUNCTION My_Function

PRINT *, “M= “, M !Error; cannot have this statement here.

END MyProgram !Error; should be END PROGRAM My_Program