Unary operator expression evaluation c

Question

After executing the program, I am getting 10 as the answer.

Please explain and give the postfix for the expression [ z=x++-y*b/a ].

Answer 1

First of all, in case of postfix expression the value used in the expression evaluation is value before changing it. So though the ++ is performed before all the other the value for x would be 10 in the expression evaluation. So postfix is x++yb*a/-

Answer 2

z =x++-y*b/a

    = 5-(-10)*2/4

   = 5-(-20)/4

= 5 - (-5) =10

o/p is 10 and finally x = 6