Fortran Function Syntax

type FUNCTION function-name (arg1, arg2, ..., argn)
! type above is of the value returned
  IMPLICIT NONE  !! must put this
  [specification part] !! declare all vars (including arg1, ..., argn)
                ! Local vars can be used inside function
  [execution part]   !! do whatever calculatoins you need.
! last statement is typically  
!  function-name = return-value
END FUNCTION function-name

• formal arguments are arg1, ..., argn
• The types and intent must be declared in specification part. (typically- INTENT(IN) means they receive information from outside and should not be changed inside the function.)
• Local vars can be used inside the function. not visible outside.
• When control reaches END FUNCTION, the most recent value stored in the function-name is returned.
• Never use the function name in the right-hand side of an expression.