Type declaration statements explicitly specify the data type of
  scalar variables.  For example, the following statements associate
  VAR1 with an 8-byte complex storage location, and VAR2 with an
  8-byte double-precision storage location:

    COMPLEX VAR1
    DOUBLE PRECISION VAR2

  You can explicitly specify the data type of a scalar variable only
  once.

  An explicit data type specification takes precedence over the type
  specified by an IMPLICIT statement.  If no explicit data type
  specification appears, any variable with a name that begins with
  the letter in the range specified in the IMPLICIT statement becomes
  the data type of the variable.

  Character type declaration statements specify that given variables
  represent character values with the length specified.  For example,
  the following statements associate the variable names INLINE, NAME,
  and NUMBER with storage locations containing character data of
  lengths 72, 12, and 9, respectively:

    CHARACTER*72 INLINE
    CHARACTER NAME*12, NUMBER*9

  In single subprograms, assumed-length character arguments can be
  used to process character strings with different lengths.  The
  assumed-length character argument has its length specified with an
  asterisk, for example:

    CHARACTER*(*) CHARDUMMY

  The argument CHARDUMMY assumes the length of the actual argument.