Java quiz 33: Conditional vs bitwise operator

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This Java quiz demonstrates the difference between conditional operator || with the bitwise operator |. To understand the difference you can play with the code and change the operators to test it.

Java quiz 33: Conditional operator vs bitwise operator

Level: Normal

What is the output of the following code?

public class MyOperator
{
  public static void main(String[] args)
  {
    int x = 1;
    int y = 2;
    if((++x == y) || (x++ == y))
    {
      if((x++ == y++) | (++x == y))
      {
        x += y;
      }
    }
    System.out.println(x);
  }
}
Author: Sar Maroof

Select the correct answer.

a. This program writes “8” to the standard output.
b. This program writes “6” to the standard output.
c. This program writes “7” to the standard output.
d. This program writes “5” to the standard output.
e. This program writes “4” to the standard output.
f. Illegal at compile time.
g. Illegal at run time.

Answer explanation

If the first boolean operand is true by conditional operator || the second boolean operand is ignored.
By the bitwise operator | all the boolean operands are evaluated regardless of their results.

  1. The statement if((++x == y) || (x++ == y)) returns true, because ++x == y. Therefore, the boolean operand x++ == y is ignored.
  2. The value of x is incremented by 1 and it becomes 2.
  3. The statement if((x++ == y++) | (++x == y)) returns true, because x++ = y++.
    Therefore, the value of x is incremented by 1. x = 3. The value of y is also incremented by 1. y = 3. The boolean operand ++x == y is also evaluated. Therefore the value of x is incremented by 1. So, x = 3 + 1 = 4.
  4. The statement x += y; increments the value of x by y, so, x = 4 + 3 = 7.

The correct answer is: c.

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Sar Maroof is graduated from HBO Amsterdam "higher professional education". He is a professional computer programming teacher, gives master classes and publishes technical articles. His experience with developing software started from 2001 and he has worked as a software developer for several big as well as small companies and later as a freelancer. He is the author of Java quizmaster and Build a Java application in 7 days.

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