ISRO-2013-64

Question

What is the output of the following program?

Class Test
{ 
    public static void main (String [] args) 
    {  
        int x = 0; 
        int y = 0 
        for (int z = 0; z < 5; z++)
        { 
            if((++x >2)||(++y  > 2)) 
            {
                x++;
            }
        }
    System.out.printIn (x+ "" + y); 
    }
}

• A. 8 2
• B. 8 5
• C. 8 3
• D. 5 3

Comments

In a lot of programming languages (including C) in case there are two arguments (or operations), and the first one's result is sufficient to get the overall result; other argument is not processed.

This is called Short Circuit Evaluation, and it can be extended to any number of arguments.

Here, 

            if((++x >2)||(++y  > 2)) 

If the first operation is True, the second operation won't be evaluated.

 

Now read the answer by @rude.

Answer 1

Before solving the questions, if we think why they asked this particular question then probability of getting correct answer increased. For example this question is an example of Short-Circuit Evaluation. 

Here is the Answer:

$z = 0$  : $x = 1$ and $y = 1$, Because $x++;$ will not be executed because condition is false

$z = 1$  : $x = 2$ and $y = 2$, Because $x++;$ will not be executed because condition is false

$z = 2$  : $x = 4$ and $y = 2$, Here $x++;$ will be executed, but $++y$ will not be executed due to short circuit evaluation

$z = 3$  : $x = 6$ and $y = 2$, Here $x++;$ will be executed, but $++y$ will not be executed due to short circuit evaluation

$z = 4$  : $x = 8$ and $y = 2$, Here $x++;$ will be executed, but $++y$ will not be executed due to short circuit evaluation

Hence at the end, It will print 8 2.

Comments

Because of pre-increment operator (++x ) Note: Value will be incremented before evaluation.

while z=2, x will be incremented by 1 in the if statement (++x >2) . Now, x value became 3. Then, again it will be incremented by 1 in inside of the if statement X++; so that x value suddenly incremented x=2 to x=4.

---

Why not y increment in if condition till 5 ?

---

because everytime after x>=3 in if condition x will always be greater than 2 and we have OR operator between ++x>2 || ++y>2. So ++x>2  will return true in If condition and ++y>2 won't be check. so ++y will not be excute once x is greater than equal to 3.