Java puzzle 01: A simple loop

  Quizzes     Assignments     Puzzles     Easy exercises     Required knowledge  
< Java Puzzles   Green = Easy,  Blue = Normal,  Red = Hard
Select    01   02   03   04   05   06   07   08   09   10   11   12   13   14   15 
 16   17   18   19   20   21   22   23   24   25   26   27   28   29   30   By title 
>

If this simple program is compiled and run, the following is written to the standard output.
-x1-x2-x3-x4-x5-x6-x7-x8-x9-x10

Add only one statement to the line 8. As a result of that the program writes “-x1-x7” to the standard output.

Java puzzle 1: A simple loop

Level: Normal

public class MyClass
{
  public static void main(String[] args)
  {
    for (int x = 1; x <= 10; x++)
    {
      System.out.print("-x" + x);
      // add a statement here!
    }
  }
}

Author: Sar Maroof

Answer explanation

  1. The loop of this program starts from the initial value of x = 1.
    each time the loop repeats, x++ increments the value of x by one until the value of x is equal to 9 or the conditional x<=10 returns false.
  2. We add the statement x += 5 on line 8. When the first time the loop is executed the statement System.out.print(“-x” + x); writes -x1 to the standard output. That is because the initial value of x is 1.
  3. The statement x += 5; increments the value of x by 5, then x++ increments the value of x by one.
  4. By the second execution of the loop, the value of x is equal to 7. The statement System.out.print(“-x” + x); writes -x7 to the standard output.
  5. The statement x +=5 increments the value of x by 5. Therefore the value of x becomes 12 and that is greater than 10. The conditional x <=10 returns false. Therefore the loop is terminated. The program writes: -x1-x7 to the standard output.

The answer is: x+=5;

public class MyClass
{
  public static void main(String[] args)
  {
    for (int x = 1; x <= 10; x++)
    {
      System.out.print("-x" + x);
      x+=5;
    }
  }
}

 





Sar Maroof is a professional software development teacher, gives master classes and publishes technical articles. He is also an expert software developer and worked for several big as well as small companies and later as a freelancer.

 Subscribe to Sar Maroof's RSS feeds!
 Mail this page to a friend!
 Bookmark this page!

Leave a Reply

Your email address will not be published. Required fields are marked *