Real and complex numbers are floating-point representations.

  COMPLEX(KIND=4) (or COMPLEX*8) data is eight contiguous bytes
  aligned on an arbitrary byte boundary.  The low-order four bytes
  contain REAL(KIND=4) (or REAL*4) data that represents the real part
  of the complex number.  The high-order four bytes contain REAL data
  that represents the imaginary part of the complex number.  For
  information on the ranges of REAL data, see REAL (within the DATA
  CONSTANTS section of online Help).

  DOUBLE COMPLEX (COMPLEX(KIND=8) or COMPLEX*16) data is 16
  contiguous bytes aligned on an arbitrary byte boundary.  The
  low-order bytes contain DOUBLE PRECISION data that represents the
  real part of the complex number.  The high-order eight bytes
  contain DOUBLE PRECISION data that represents the imaginary part of
  the complex data.  For information on the ranges of DOUBLE
  PRECISION data, see DOUBLE_PRECISION (within the DATA CONSTANTS
  section of online Help).

  COMPLEX(KIND=16) (or COMPLEX*32) data is 32 contiguous bytes
  aligned on an arbitrary byte boundary.  The low-order bytes contain
  REAL(KIND=16) (or REAL*16) data that represents the real part of
  the complex number.  The high-order bytes contain REAL*16 data that
  represents the imaginary part of the complex number.  For
  information on the ranges of REAL*16 data, see REAL (within the
  DATA CONSTANTS section of online Help).