Ch1, Ex10

%(a)
We almost never see 1 because chances of happening thread interleaving are very low.

% (b)

declare
C={NewCell 0}
thread I in
  I=@C
  {Delay 5000}
  C:=I+1
end
thread J in
  J=@C
  C:=J+1
  {Delay 5000}
end

Above code almost always results in C being 1 and reason is pretty trivial to figure out.

% (c) -
Since there is a lock, so other thread can't enter the locked block unless the first thread releases it so interleaving is not possible and hence we never see 1 even if we add delay.