Concurrent Processes

Question

Consider the program segment:
x= 0; y=0;
Cobegin
begin
x= 1;
y= y + x;
end
begin
y= 2;
x= x + 3;
end
Coend;
Which of the following indicates possible values for the variables when the segment finishes
execution?
(1) x= 1, y= 2
(2) x= 1, y= 3
(3) x= 4, y= 6
(a) 1 only (b) 1 & 2 only
(c) 1 & 3 only (d) 2 & 3 only
(e) 1, 2, 3

Answer 1

x= 1;   ....1
y= y + x; ....2
y= 2;.....3
x= x + 3;....4

Consider following order 3,4,1,2 i.e Y=2,X=0+3,X=1,Y=1+2  so 1,3

Consider the following order 1,3,4,2 i.e X=1,Y=2,X=1+3,Y=2+4 so 4,6

so option D only 2 and 3