The real data type
The real data type represents a 64-bit wide, double-precision, floating-point number.
Literals of the real data type have the same representation as .NET's System.Double. 1.0, 0.1, and 1e5 are all literals of type real.
There are several special literal forms:
real(null): The is the null value.real(nan): Not-a-Number (NaN). For example, the result of dividing a0.0by another0.0.real(+inf): Positive infinity. For example, the result of dividing1.0by0.0.real(-inf): Negative infinity. For example, the result of dividing-1.0by0.0.