Funct mod

Hi,

Now i am getting this error.

when I am checking for syntax error iam getting this error. This is the program that is present in function group. when i tried to activate that also I got the error that Report/program statement is missing.

Program SAPLZAC_GRP 2

REPORT/PROGRAM statement missing, or program type is I (INCLUDE).

FUNCTION ZAC_CALCULATE.

*"----

""Local Interface:

*" IMPORTING

*" REFERENCE(IM_NUM1) TYPE I

*" REFERENCE(IM_NUM2) TYPE I

*" REFERENCE(IM_OPER) TYPE C

*" EXPORTING

*" REFERENCE(EX_RESULT) TYPE I

*"----

CASE IM_OPER.

WHEN '+'.

EX_RESULT=IM_NUM1+IM_NUM2.

WHEN '-'

EX_RESULT=IM_NUM1-IM_NUM2.

WHEN '*'

EX_RESULT=IM_NUM1*IM_NUM2.

ENDCASE.

ENDFUNCTION.