A. Consider the square() method shown below that takes a non-negative int argument. Complete the code for the square() method so that it correctly calls the squareHelper() method to produce the square of n.

public int square(int n) { ____________________; } public int squareHelper(int c, int n) { if (c == 1) { return n; } else { return n + squareHelper(c - 1, n); } }

1.	return squareHelper(n, n - 1)

2.	return square(n)

3.	return squareHelper(n, n)

4.	return squareHelper(n - 1, n)

B. Consider the permutations() method from the textbook, which is intended to return all permutations of the word passed in as a parameter. How does the permutations() method simplify its input for the recursive call?

public static ArrayList permutations(String word) { ArrayList result = new ArrayList(); if (word.length() == 0) { result.add(word); return result; } else { for (int i = 0; i < word.length(); i++) // line #4 { String shorter = word.substring(0, i) + word(substring(i + 1)); ArrayList shorterPermutations = permutations(shorter); for (String s : shorterPermutations) { result.add(word.charAt(i) + s); } } return result; } }

1.	It finds permutations of a shorter word by removing the last character.

2.	It finds permutations of a shorter word by removing both the first and last character.

3.	It finds permutations of a shorter word by removing the first character.

4.	It finds permutations of shorter words formed by removing the ith character.

C. Consider the getArea() method from the textbook shown below.

public int getArea() { if (width <= 0) // line #1 { return 0; // line #2 } else if (width == 1) // line #3 { return 1; // line #4 } else { Triangle smallerTriangle = new Triangle(width - 1); // line #5 int smallerArea = smallerTriangle.getArea(); // line #6 return smallerArea + width; // line #7 } }

Where is/are the recursive call(s)?

1.	lines #1 and #3

2.

line #3

3.

line #6

4.

line #1

D. Consider the helper method reversePrint, which uses recursion to display in reverse the elements in a section of an array limited by the firstIndex and lastIndexarguments. What statement should be used to complete the recursive method?

public static void reversePrint(int[] array, int firstIndex, int lastIndex) { if (firstIndex < lastIndex) { reversePrint(array, firstIndex + 1, lastIndex); } System.out.println(_________________); } public static void main(String[] args) { int [] numbers = { 4, 7, 1, 0, 2, 7 }; reversePrint(numbers, 0, numbers.length - 1); }

1.	array[lastIndex]

2.	array[firstIndex]

3.	array[lastIndex - 1]

4.	array[firstIndex + 1]