Given the code fragment: 3. public static void main(String[] args) { 4. int x = 5; 5. while (isAvailable(x)) { 6. System.out.print(x); 7. } 8. } 9. 10. public static boolean isAvailable(int x) { 11…

The correct answer is B. At line 7, insert x --. Option B works because inserting x--; after the print statement decrements x in main's scope on each iteration. Since isAvailable receives a primitive copy, the x-- inside it never affects main's x - so without the fix, x stays 5 forever and the loop is infinite. With x…

Using Loop Constructs

Question

Given the code fragment:
public static void main(String[] args) {
int x = 5;
while (isAvailable(x)) {
System.out.print(x);
}
}
public static boolean isAvailable(int x) {
return x-- > 0 ? true : false;
}

Which modification enables the code to print 54321?

Options

AReplace line 6 with System. out. print (-x);
BAt line 7, insert x --;
CReplace line 6 with --x; and, at line 7, insert System. out. print (x);
DReplace line 12 With return (x > 0) ? false: true;

How the community answered

(70 responses)

A
4% (3)
B
70% (49)
C
19% (13)
D
7% (5)

Explanation

Option B works because inserting x--; after the print statement decrements x in main's scope on each iteration. Since isAvailable receives a primitive copy, the x-- inside it never affects main's x - so without the fix, x stays 5 forever and the loop is infinite. With x-- inserted at line 7, the loop prints 5, then 4, 3, 2, 1 before isAvailable(0) returns false and exits.

Why the distractors fail:

A (-x in print): Negates x for display purposes only but still doesn't decrement main's x, so it infinite-loops printing -5.
C (--x then print): The pre-decrement fires before printing, so it outputs 43210 instead of 54321.
D (inverted condition): Returns false when x > 0, so the loop never enters at all - no output.

Memory tip: In Java, primitives are pass-by-value - any mutation inside a called method is invisible to the caller. Whenever a loop counter lives in a method that only receives a copy, you must decrement it in the calling scope to actually make progress.

Topics

#Post-decrement operator#Method parameters#While loop#Loop termination

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