Java quiz 15: Loop within loop

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For many of the projects on which I worked, I needed to use loops within loops. In the beginning seems very hard, but if you understand the process you become gradually familiar with it.

Java quiz 15: Loop within loop

Level: Hard

What is the output of this code?

public class MyLoop
  public static void main(String[] args)
    int y = 0;
    while(y < 14)
      for(int i = 1; i < 4; i++)
        y += i;
Author: Sar Maroof

Select the correct answer.

Answer explanation

  1. If y is smaller than 14 the body of the while loop is executed. The initial value of y is 0.
  2. When the body of the while loop is excuted the statement y++; increments the value of y by 1. y = 0 + 1 = 1.
  3. The second loop is a for loop. The initial value of i is 1 and the body of the loop is executed as long as y is smaller than 4. This loop is executed for the values of i 1, 2, 3. The statement y += i increments the value of y by i. So, y = 1 + 1 + 2 + 3 = 7.
  4. The last value of y is 7 and that is smaller than 14. The body of the while loop is executed for the second time and y ++; increments the value of y by 1, y = 7 + 1 = 8.
  5. The body of the for loop is executed and the statement y += i increments the value of y by i and those are 1, 2, 3. So, y = 8 + 1 + 2 + 3 = 14. The while loop is terminated because y is no longer smaller than 14.

The correct answer is: b.

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Please, leave your questions, feedback and suggestions in the comments below! offers a practical method to learn and improve your Java skills. It avoids unnecessary long boring theoretical explanations, but it uses many exercises and quizzes.

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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