A complex constant approximates the value of a mathematical complex number. The constant is a pair of real or integer values, separated by a comma, and enclosed in parentheses. The first constant represents the real part of that number; the second constant represents the imaginary part.
The following is the general form of a complex constant:
(c,c)
Is as follows:
For COMPLEX(4) constants, c is an integer or REAL(4) constant.
For COMPLEX(8) constants, c is an integer, REAL(4) constant, or DOUBLE PRECISION (REAL(8)) constant. At least one of the pair must be DOUBLE PRECISION.
For COMPLEX(16) constants, c is an integer, REAL(4) constant, REAL(8) constant, or REAL(16) constant. At least one of the pair must be a REAL(16) constant.
Note that the comma and parentheses are required.