Question 1

Consider the getArea method from the textbook shown below.   What will be the result?

Accepted Answer

A) The method will return incorrect results for triangles with width equal to 0. 
B) The method will return incorrect results for triangles with width equal to 1. 
C) The method will return area to be one too high for all triangles. 
D) The method will still return correct results for all non-negative width triangles. 
A) The method will return incorrect results for triangles with width equal to 0. 
B) The method will return incorrect results for triangles with width equal to 1. 
C) The method will return area to be one too high for all triangles. 
D) The method will still return correct results for all non-negative width triangles. D

Question 2

Consider the following recursive code snippet:   What parameter values for n would cause an infinite recursion problem in the following method?

Accepted Answer

A) all n with n = 0 
D) n == 1 
A) all n with n = 0 
D) n == 1 A

Question 3

Consider the getArea method from the textbook shown below:   If line #1 was eliminated from the method, what would be the result when calling getArea?

Accepted Answer

A) A positive width would reduce the correct area by 1. 
B) We would lose our only recursive case. 
C) Nothing - the method would still work correctly. 
D) A negative or zero width would cause problems. 
A) A positive width would reduce the correct area by 1. 
B) We would lose our only recursive case. 
C) Nothing - the method would still work correctly. 
D) A negative or zero width would cause problems. D

Question 4

Consider the following code snippet for calculating Fibonacci numbers recursively:   Identify the terminating condition in this recursive method.

Accepted Answer

A) n < 1 
B) n <= 1 
C) fib(n - 1) 
D) fib(n - 1) + fib(n - 1) 
A) n < 1 
B) n <= 1 
C) fib(n - 1) 
D) fib(n - 1) + fib(n - 1)

Question 5

Consider the mutually recursive methods below.Select the method call that could be used to generate the output sequence: A5 B4 A3 B2 A1

Accepted Answer

A) methodA(5); 
B) methodA(4); 
C) methodB(5); 
D) methodB(4); 
A) methodA(5); 
B) methodA(4); 
C) methodB(5); 
D) methodB(4);

Question 6

How many recursive calls to the fib method shown below would be made from an original call to fib(4)? (Do not count the original call)

Accepted Answer

A) 8 
B) 4 
C) 1 
D) 2 
A) 8 
B) 4 
C) 1 
D) 2

Question 7

Consider the permutations method from the textbook, which is intended to return all permutations of the word passed in as a parameter.   If line #8 is changed to add the removed character to the end of each permutation of the shorter word, which change best describes the returned list?
result.add(s + word.charAt(i)); // line #8 revised

Accepted Answer

A) It contains all permutations. 
B) It is an incomplete list of permutations. 
C) It contains strings that are not permutations. 
D) It contains duplicates of some permutations. 
A) It contains all permutations. 
B) It is an incomplete list of permutations. 
C) It contains strings that are not permutations. 
D) It contains duplicates of some permutations.

Question 8

Consider the method powerOfTwo shown below:   How many recursive calls are made from the original call powerOfTwo(63) (not including the original call)?

Accepted Answer

A) 1 
B) 6 
C) 0 
D) 4 
A) 1 
B) 6 
C) 0 
D) 4

Question 9

Complete the following code snippet, which is intended to determine if a value is even or odd using mutual recursion:

Accepted Answer

A) return true; 
B) return false; 
C) return isOdd(Math.abs(n)); 
D) return isOdd(Math.abs(n)-1); 
A) return true; 
B) return false; 
C) return isOdd(Math.abs(n)); 
D) return isOdd(Math.abs(n)-1);

Question 10

In recursion, the non-recursive case is analogous to a loop ____.

Accepted Answer

A) termination 
B) call 
C) iteration 
D) condition 
A) termination 
B) call 
C) iteration 
D) condition

Question 11

A palindrome is a word or phrase that reads the same forward or backward.Consider the following code snippet:   What is the purpose of the palindrome method?

Accepted Answer

A) Recursively call itself. 
B) Provide the string, along with its first and last indexes to the recursive isPal method. 
C) Send the recursive isPal method its terminating condition. 
D) Return the palindrome to the calling method. 
A) Recursively call itself. 
B) Provide the string, along with its first and last indexes to the recursive isPal method. 
C) Send the recursive isPal method its terminating condition. 
D) Return the palindrome to the calling method.

Question 12

Which statement is true about backtracking?

Accepted Answer

A) Backtracking starts with a partial solution and builds it up to get closer to the goal. 
B) Backtracking never abandons a partial solution. 
C) Backtracking starts from the end of the program and works backward to the beginning. 
D) Backtracking explores only one path toward a solution 
A) Backtracking starts with a partial solution and builds it up to get closer to the goal. 
B) Backtracking never abandons a partial solution. 
C) Backtracking starts from the end of the program and works backward to the beginning. 
D) Backtracking explores only one path toward a solution

Question 13

Which problem-solving technique examines partial solutions, abandons unsuitable ones, and returns to consider other candidate solutions.

Accepted Answer

A) Backtracking 
B) Recursion 
C) Traceback 
D) Debugging 
A) Backtracking 
B) Recursion 
C) Traceback 
D) Debugging

Question 14

Consider the iterative version of the fib method from the textbook shown below:   How many iterations of the for loop will there be for the call fib(6)?

Accepted Answer

A) 3 
B) 5 
C) 6 
D) 4 
A) 3 
B) 5 
C) 6 
D) 4

Question 15

In recursion, the recursive call is analogous to a loop ____.

Accepted Answer

A) termination 
B) iteration 
C) call 
D) return 
A) termination 
B) iteration 
C) call 
D) return

Question 16

Given the following code snippet:   What value will be returned when this code is executed with a call to newCalc(5)?

Accepted Answer

A) 5 
B) 1.5 
C) 5.5 
D) 1 
A) 5 
B) 1.5 
C) 5.5 
D) 1

Question 17

Consider the getArea method from the textbook shown below:   This would cause infinite recursion for ____.

Accepted Answer

A) triangles with width equal to 1 
B) triangles with width equal to 0 
C) triangles with width greater than or equal to 2 
D) triangles of any width 
A) triangles with width equal to 1 
B) triangles with width equal to 0 
C) triangles with width greater than or equal to 2 
D) triangles of any width

Question 18

Consider the method below, which displays the characters from a String in reverse order.Each character appears on a separate line.Select the statement that should be used to complete the method so that it performs a recursive method call correctly.

Accepted Answer

A) printReverse(word.length() - 1); 
B) printReverse(word.substring(1)); 
C) printReverse(word); 
D) printReverse(new String(word.charAt(1))); 
A) printReverse(word.length() - 1); 
B) printReverse(word.substring(1)); 
C) printReverse(word); 
D) printReverse(new String(word.charAt(1)));

Question 19

Consider the recursive version of the fib method from the textbook shown below:   How many total recursive calls (not counting the original call) to fib will be made from the original call of fib(7)?

Accepted Answer

A) 12 
B) 32 
C) 24 
D) 30 
A) 12 
B) 32 
C) 24 
D) 30

Question 20

Given the following class code:   What values will be printed when this code is executed?

Accepted Answer

A) 4 
B) 8 
C) 0, 4, and 8 
D) 4 and 8 
A) 4 
B) 8 
C) 0, 4, and 8 
D) 4 and 8

Exam 13: Recursion

Consider the getArea method from the textbook shown below. What will be the result?

Consider the following recursive code snippet: What parameter values for n would cause an infinite recursion problem in the following method?

Consider the getArea method from the textbook shown below: If line #1 was eliminated from the method, what would be the result when calling getArea?

Consider the following code snippet for calculating Fibonacci numbers recursively: Identify the terminating condition in this recursive method.

Consider the mutually recursive methods below.Select the method call that could be used to generate the output sequence: A5 B4 A3 B2 A1

How many recursive calls to the fib method shown below would be made from an original call to fib(4)? (Do not count the original call)

Consider the method powerOfTwo shown below: How many recursive calls are made from the original call powerOfTwo(63) (not including the original call)?

Complete the following code snippet, which is intended to determine if a value is even or odd using mutual recursion:

In recursion, the non-recursive case is analogous to a loop ____.

A palindrome is a word or phrase that reads the same forward or backward.Consider the following code snippet: What is the purpose of the palindrome method?

Which statement is true about backtracking?

Which problem-solving technique examines partial solutions, abandons unsuitable ones, and returns to consider other candidate solutions.

Consider the iterative version of the fib method from the textbook shown below: How many iterations of the for loop will there be for the call fib(6)?

In recursion, the recursive call is analogous to a loop ____.

Given the following code snippet: What value will be returned when this code is executed with a call to newCalc(5)?

Consider the getArea method from the textbook shown below: This would cause infinite recursion for ____.

Consider the method below, which displays the characters from a String in reverse order.Each character appears on a separate line.Select the statement that should be used to complete the method so that it performs a recursive method call correctly.

Consider the recursive version of the fib method from the textbook shown below: How many total recursive calls (not counting the original call) to fib will be made from the original call of fib(7)?

Given the following class code: What values will be printed when this code is executed?

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