Returns a hexadecimal string representation of the double argument. All characters mentioned below are ASCII characters.

If the argument is NaN, the result is the string " NaN".
Otherwise, the result is a string that represents the sign and magnitude of the argument. If the sign is negative, the first character of the result is ' -' ( '\u002D'); if the sign is positive, no sign character appears in the result. As for the magnitude m:
- If m is infinity, it is represented by the string "Infinity"; thus, positive infinity produces the result "Infinity" and negative infinity produces the result "-Infinity".
- If m is zero, it is represented by the string "0x0.0p0"; thus, negative zero produces the result "-0x0.0p0" and positive zero produces the result "0x0.0p0".
- If m is a double value with a normalized representation, substrings are used to represent the significand and exponent fields. The significand is represented by the characters "0x1." followed by a lowercase hexadecimal representation of the rest of the significand as a fraction. Trailing zeros in the hexadecimal representation are removed unless all the digits are zero, in which case a single zero is used. Next, the exponent is represented by "p" followed by a decimal string of the unbiased exponent as if produced by a call to Integer.toString on the exponent value.
- If m is a double value with a subnormal representation, the significand is represented by the characters "0x0." followed by a hexadecimal representation of the rest of the significand as a fraction. Trailing zeros in the hexadecimal representation are removed. Next, the exponent is represented by "p-1022". Note that there must be at least one nonzero digit in a subnormal significand.

Examples
Floating-point Value	Hexadecimal String
`1.0`	`0x1.0p0`
`-1.0`	`-0x1.0p0`
`2.0`	`0x1.0p1`
`3.0`	`0x1.8p1`
`0.5`	`0x1.0p-1`
`0.25`	`0x1.0p-2`
`Double.MAX_VALUE`	`0x1.fffffffffffffp1023`
`Minimum Normal Value`	`0x1.0p-1022`
`Maximum Subnormal Value`	`0x0.fffffffffffffp-1022`
`Double.MIN_VALUE`	`0x0.0000000000001p-1022`

Parameters:

d the double to be converted.

Returns: a hex string representation of the argument.

Since: 1.5