double                  Double-Precision Floating-Point Data Type

    The double type declares an object to be of "double-precision"
    floating-point type.  The size (and representation) of a double
    object is implementation-defined.  A double is the same or greater in
    size than a float.

      Notes:    In Turbo C+, the size of a double object is eight
                bytes. The range of values is approximately 1.7E-308 to
                1.7E+308.

                All floating constants have type double. You can coerce a
                floating constant to type float by adding an `F' suffix
                to the constant.

                The decision between using double and float is one of
                space versus run-time conversion cost.

                In Turbo C++, both doubles and long doubles are eight
                bytes.

   -------------------------------- Example ---------------------------------

           double value = 1.234;
           double d1 = 1.234E-24;

           value = (double) 123;