Generate Random numbers without using any external functions

Question

This was questions asked in one of the interviews that I recently attended.

As far as I know a random number between two numbers can be generated as follows

Answer 1

You can get near randomness (actually chaotic and definitely not uniform*) from the logistic map x = 4x(1-x) starting with a "non-rational" x between 0 and 1.

The "randomness" appears because of the rounding errors at the edge of the accuracy of the floating point representation.

(*)You can undo the skewing once you know it is there.