Question

Evaluate the following expression where prefix and postfix increment and decrement operator is used.

int p=3, q=20, r=0; 

r = ++p + p++ + q++ + q++;

System.out.println ("P=" + p+ “Q="+ q+ “R="+ r);

Answer 1

++p (Prefix): Increments p first (from 3 to 4), then uses this new value (4) in the expression. Now, p = 4.

p++ (Postfix): Uses the current value of p (4) in the expression, then increments p to 5. Now, p = 5.

q++ (Postfix): Uses the current value of q (20) in the expression, then increments q to 21. Now, q = 21.

q++ (Postfix): Uses the current updated value of q (21) in the expression, then increments q to 22. Now, q = 22

• R = 4 + 4 + 20 + 21 = 49
• P = 5
• Q = 22