If a = 5, b = 9, calculate the value of a in the following expression:
a += a++ - ++b + a

6

Working

    a += a++ - ++b + a
⇒ a = a + (a++ - ++b + a)
⇒ a = 5 + (5 - 10 + 6) [∵ a++ will first use current value of a then increment it to 6. ++b will increment b to 10 and use the incremented value. As a++ incremented a to 6 so the value of last a in the expression is 6]
⇒ a = 5 + 1
⇒ a = 6