A single-precision REAL constant occupies four bytes of memory. The number of digits is unlimited, but typically only the leftmost seven digits are significant.
On Tru64 UNIX, Linux, Windows NT, and Windows 9* systems, IEEE® S_floating format is used. On OpenVMS systems, either Compaq VAX F_floating or IEEE S_floating format is used, depending on the compiler option specified.
The following examples show valid and invalid REAL(4) constants:
| Valid | |
3.14159 | |
3.14159_4 | |
621712._4 | |
-.00127 | |
+5.0E3 | |
2E-3_4 | |
| Invalid | Explanation |
1,234,567. | Commas not allowed. |
325E-47
| Too small for REAL; this is a valid DOUBLE PRECISION constant. |
-47.E47
| Too large for REAL; this is a valid DOUBLE PRECISION constant. |
625._6
| 6 is not a valid kind for reals. |
100 | Decimal point missing; this is a valid integer constant. |
$25.00 | Special character not allowed. |