I couldn't find any (like not a single one), so I wrote a program myself to do it: http://blog.reverberate.org/2012/11/dumpfp-tool-to-inspect-f...
If you know of a program in any of these languages that will print this value for "0.1" using built-in functionality, please let me know because I would love to know about it.
Likewise the precise value of double(1e50) is 100000000000000007629769841091887003294964970946560. Anything else is an approximation of its true value.
In another message you said that what's really important is that the string representation uniquely identifies the precise value. While that will help you reconstruct the value later, it does not help you understand why 0.1 + 0.2 != 0.3.
>>> from decimal import Decimal
>>> Decimal(0.1)
Decimal('0.1000000000000000055511151231257827021181583404541015625')
>>> Decimal(1e50)
Decimal('100000000000000007629769841091887003294964970946560') toRational 0.1 = 3602879701896397 % 36028797018963968
toRational 1e50 = 100000000000000007629769841091887003294964970946560 % 1
julia> big(0.1)
1.000000000000000055511151231257827021181583404541015625e-01
julia> big(1e50)
1.0000000000000000762976984109188700329496497094656e+50
julia> BigFloat("0.1")
1.000000000000000000000000000000000000000000000000000000000000000000000000000002e-01
julia> BigFloat("1e50")
1e+50 rasky at monocle in ~
↪ python
Python 2.7.5 (default, Sep 2 2013, 05:24:04)
[GCC 4.2.1 Compatible Apple LLVM 5.0 (clang-500.0.68)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> 0.1
0.1
>>> ^D
rasky at monocle in ~
↪ python3
Python 3.3.3 (default, Dec 24 2013, 13:54:32)
[GCC 4.2.1 Compatible Apple LLVM 5.0 (clang-500.2.79)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> 0.1
0.1