Question

What will be the answer to :

class abcd
{
  public static void main(String ar[])
  {
    int a=2, b=3, c;
    c = a++ * --b - b++ + ++a;
    System.out.println(a+" "+b+" "+c);
  }
}

Compiler gave the output as : 4 3 6. I got a=4 and b=3, but i was unable to solve for c. I came out with c=7.

Too much confusion in operator precedence. Someone plz help. 🙁

Answer 1

Operands are evaluated left to right, so your code is equivalent to:

int a = 2, b = 3, c = 0;
int tmp1 = a++; //tmp1 = 2, a = 3
int tmp2 = --b; //tmp2 = 2, b = 2
int tmp3 = b++; //tmp3 = 2, b = 3
int tmp4 = ++a; //tmp4 = 4, a = 4
c = tmp1 * tmp2 - tmp3 + tmp4; // c = 2 * 2 - 2 + 4 = 6

As for the link you posted, it only says that the formula should be read as:

c = ( ( (a++) * (--b) ) - (b++) + (++a) );