Question

From this sample code from MSDN
http://msdn.microsoft.com/en-us/library/system.string.gethashcode.aspx

The hash code for “abc” is: 536991770

But how to convert back the “536991770” to “abc”?

Answer 1

The is no way to get value from the hashcode. See hash-function definition.
Hash values are not used to uniquely identify the original value, have values are not unique for each type of the input value.

A hash function may map two or more
keys to the same hash value. In many
applications, it is desirable to
minimize the occurrence of such
collisions, which means that the hash
function must map the keys to the hash
values as evenly as possible.