Why initialize a new Random() with unchecked(Environment.TickCount * 31)?

Question

I found this initialization of a Random instance:

var random = new Random(unchecked(Environment.TickCount * 31));

Why not simply use new Random()?

Answer 1

The keyword unchecked prevents an exception from being thrown when the calculation Environment.TickCount * 31 integer overflows.

The resulting calculation is essentially a random integer (it throws away a bunch of high-order bits), which is used to seed the random number generator.

Note that the Reference Source for Random has this code as its parameterless constructor:

public Random() 
    : this(Environment.TickCount) {
  }