Statement: Specifies the DOUBLE PRECISION data type.
Syntax
DOUBLE PRECISION
A REAL(8) or DOUBLE PRECISION constant has more than twice the accuracy of a REAL(4) number, and greater range.
A REAL(8) or DOUBLE PRECISION constant occupies eight bytes of memory. The number of digits that precede the exponent is unlimited, but typically only the leftmost 15 digits are significant.
IEEE* T_floating format is used.
For more information, see General Rules for Real Constants.
See Also
REAL Statement, REAL(8) or DOUBLE PRECISION Constants, Data Types, Constants, and Variables, Real Data Types
Examples
DOUBLE PRECISION varnam
DOUBLE PRECISION,PRIVATE :: zz
The following examples show valid and invalid REAL(8) or DOUBLE PRECISION constants:
| Valid | |
| 123456789D+5 | |
| 123456789E+5_8 | |
| +2.7843D00 | |
| -.522D-12 | |
| 2E200_8 | |
| 2.3_8 | |
| 3.4E7_8 | |
| Invalid | Explanation |
| -.25D0_2 | 2 is not a valid kind type for reals. |
| +2.7182812846182 | No D exponent designator is present; this is a valid single-precision constant. |
| 123456789.D400 | Too large for any double-precision format. |
| 123456789.D-400 | Too small for any double-precision format. |