Unit 2 · Selection and Iteration

While Loops

Practice mode with 15 Java-focused questions, immediate answer checks, and explanations.

What while loops covers

A while loop checks its condition before each iteration and keeps running until that condition becomes false. Unlike a for loop, nothing updates the control variable automatically, so the body must change it. While loops fit situations where the number of iterations is not known in advance, such as processing digits of a number or reading until a sentinel value appears.

Where students lose points

Forgetting to update the control variable produces an infinite loop, and questions test whether students notice it. The opposite error is updating in the wrong place, which skips the first or last value. Students also confuse a while loop that may run zero times with a do-while that always runs at least once.

How it shows up on the AP exam

Unit 2 iteration. While loops carry the digit-extraction and sentinel-processing questions on the MCQ, and they appear in FRQs whenever the stopping point depends on the data rather than on a fixed count.

For practice use only.

While Loops MCQ Practice

AP CSA while loop practice: entry conditions, updating the control variable, infinite-loop traps, and sentinel patterns tested on the exam.

Question 1 of 15

Answered 0 of 15

Choose one answer.

Which option matches the complete output produced by this segment?

public class WhileLoopsContext
{
    public static void runExample()
    {
        int n = 3;
        while (n > 0)
        {
            System.out.print(n);
            n--;
        }
    }

    public static void main(String[] args)
    {
        runExample();
    }
}

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