Fortran 90 - gfortran error - help

[Bussell93]

Hi, I have written a fortran 90 program that finds the definite integral of a function using the trapezium method.

Everything is fine, other than when I compile my program it produces the following error:

assignment_2_final.f90:127.2:

ITRAP = (z/2)((G(a) + G(b)) + z*area)
1
Error: Unclassifiable statement at (1)

My code looks like this...

PROGRAM assignment_2
IMPLICIT NONE

REAL(kind = 8) :: x, h, Error_F, Error_C, Error_D2, a, b, z, area, ITRAP
INTEGER :: i, N

area = 0.0

...

z = b - a

DO i=1,N-1
area = area + G(a+i*z)
END DO

ITRAP = (z/2)((G(a) + G(b)) + z*area)

WRITE(6,*)
WRITE(6,*)'The definite integral of g(x) using'
WRITE(6,*)'the trapezium rule = ',ITRAP
WRITE(6,*)

The user is asked to enter values for a, b and N.

I have changed the code and still cannot come up with the solution to my error, any help would be greatly appreciated

 

[DrClaude]

ITRAP = (z/2)((G(a) + G(b)) + z*area)

That should be

ITRAP = (z/2)*((G(a) + G(b)) + z*area)

(Please use

 tags when posting code.)

 

[Bussell93]

this made me feel very stupid! sometimes the answer is right in front of your face. Thanks a lot! Will do for next time.