Question 1

Consider the getArea method from the textbook shown below:

Accepted Answer

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

Question 2

Complete the following code snippet, which is intended to be a recursive method that will find the sum of all elements in an array of double values from the beginning of the array to index:

Accepted Answer

A) return (arr[index] + findSum(arr, index + 1)); 
B) return (findSum(arr, index - 1)); 
C) return (findSum(arr, index + 1)); 
D) return (arr[index] + findSum(arr, index - 1)); 
A) return (arr[index] + findSum(arr, index + 1)); 
B) return (findSum(arr, index - 1)); 
C) return (findSum(arr, index + 1)); 
D) return (arr[index] + findSum(arr, index - 1));

Question 3

Which of the following options could be used as a terminating condition for a recursive method that finds the middle character of a String with any number of characters?
i.the length of the String is 1
II.first and last String characters match
III.the String is not empty

Accepted Answer

A) I only 
B) I and III only 
C) I, II and III 
D) II only 
A) I only 
B) I and III only 
C) I, II and III 
D) II only

Question 4

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?

Accepted Answer

A) It finds permutations of a shorter word by removing both the first and last character. 
B) It finds permutations of a shorter word by removing the last character. 
C) It finds permutations of shorter words formed by removing the ith character. 
D) It finds permutations of a shorter word by removing the first character. 
A) It finds permutations of a shorter word by removing both the first and last character. 
B) It finds permutations of a shorter word by removing the last character. 
C) It finds permutations of shorter words formed by removing the ith character. 
D) It finds permutations of a shorter word by removing the first character.

Question 5

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 lastIndex arguments.What statement should be used to complete the recursive method?

Accepted Answer

A) array[firstIndex] 
B) array[firstIndex+1] 
C) array[lastIndex-1] 
D) array[lastIndex] 
A) array[firstIndex] 
B) array[firstIndex+1] 
C) array[lastIndex-1] 
D) array[lastIndex]

Question 6

Consider the fib method from the textbook shown below:   Computing the 7th fibonacci number, fib(7), recursively computes fib(6), fib(5), and fib(4) ___ times respectively.

Accepted Answer

A) 6, 5, and 4 
B) 3, 2, and 1 
C) 1, 2, and 3 
D) 4, 5, and 6 
A) 6, 5, and 4 
B) 3, 2, and 1 
C) 1, 2, and 3 
D) 4, 5, and 6

Question 7

Consider the method below, which implements the exponentiation operation recursively.Select the statement that should be used to complete the method so that it handles the special case correctly.

Accepted Answer

A) return 0; 
B) return 1 * power(base, exponent - 1); 
C) return base; 
D) return 1; 
A) return 0; 
B) return 1 * power(base, exponent - 1); 
C) return base; 
D) return 1;

Question 8

A palindrome is a word or phrase spelled which reads the same forward or backward.Consider the following code snippet:   What does the method palindrome return?

Accepted Answer

A) false 
B) a palindrome not found exception 
C) the Boolean value returned from the isPal method 
D) true 
A) false 
B) a palindrome not found exception 
C) the Boolean value returned from the isPal method 
D) true

Question 9

A palindrome is a word or phrase that reads the same forward or backward.Consider the methods palindrome and isPal shown below:   The method isPal as shown here would be considered to be a ____ method.

Accepted Answer

A) terminating 
B) static 
C) recursive helper 
D) public 
A) terminating 
B) static 
C) recursive helper 
D) public

Question 10

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

Accepted Answer

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

Question 11

Consider the recursive version of the fib method from the textbook shown below:   How many recursive calls to fib(2) will be made from the original call of fib(6)?

Accepted Answer

A) 4 
B) 3 
C) 5 
D) 2 
A) 4 
B) 3 
C) 5 
D) 2

Question 12

Would switching the special case order affect the return value of the following method?

Accepted Answer

A) An exception will be thrown. 
B) Yes 
C) No 
D) It is impossible to tell. 
A) An exception will be thrown. 
B) Yes 
C) No 
D) It is impossible to tell.

Question 13

Complete the following code snippet, which is intended to be a recursive method that will find the smallest value in an array of double values from index to the end of the array:

Accepted Answer

A) minVal(elements, index - 1) 
B) minVal(index - 1) 
C) minVal(elements, index + 1) 
D) minVal(index + 1) 
A) minVal(elements, index - 1) 
B) minVal(index - 1) 
C) minVal(elements, index + 1) 
D) minVal(index + 1)

Question 14

Consider the code for the recursive method mystery shown in this code snippet:   What will be printed by the statement System.out.println(mystery(-4));?

Accepted Answer

A) Nothing - a StackoverflowError exception will occur 
B) 0 
C) -22 
D) -10 
A) Nothing - a StackoverflowError exception will occur 
B) 0 
C) -22 
D) -10

Question 15

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

Accepted Answer

A) 2.5 
B) 5.5 
C) 5 
D) 2 
A) 2.5 
B) 5.5 
C) 5 
D) 2

Question 16

Consider the method powerOfTwo shown below:   How many recursive calls are made from the original call of powerOfTwo(64) (not including the original call)?

Accepted Answer

A) 6 
B) 4 
C) 8 
D) 2 
A) 6 
B) 4 
C) 8 
D) 2

Question 17

In a _____________, a set of cooperating methods calls each other repeatedly.

Accepted Answer

A) infinite recursion 
B) permutation 
C) mutual recursion 
D) stack overflow error 
A) infinite recursion 
B) permutation 
C) mutual recursion 
D) stack overflow error

Question 18

Consider the code for the myFactorial recursive method shown below, which is intended to compute the factorial of the value passed to the method:   If you set a breakpoint on line #2 and then call myFactorial(4), how many calls to myFactorial will be visible on the debugger's call stack when the program suspends for the breakpoint?

Accepted Answer

A) 0 because the answer was returned 
B) 3 
C) 4 
D) 1 
A) 0 because the answer was returned 
B) 3 
C) 4 
D) 1

Question 19

The method below generates all nonempty substrings of a word passed as argument.Assuming that the string contains no duplicate characters, select the statement to complete the method so that it prints all nonempty substrings correctly.

Accepted Answer

A) printSubstrings(word.substring(0)); 
B) printSubstrings(word.substring(1)); 
C) printSubstrings(word.substring(word.length())); 
D) printSubstrings(word.substring(word.length() - 1)); 
A) printSubstrings(word.substring(0)); 
B) printSubstrings(word.substring(1)); 
C) printSubstrings(word.substring(word.length())); 
D) printSubstrings(word.substring(word.length() - 1));

Question 20

If a recursive method does not simplify the computation within the method and the base case is not called, what will be the result?

Accepted Answer

A) The recursion calculation will occur correctly regardless. 
B) Infinite recursion will occur. 
C) This cannot be determined. 
D) The terminating condition will be executed and recursion will end. 
A) The recursion calculation will occur correctly regardless. 
B) Infinite recursion will occur. 
C) This cannot be determined. 
D) The terminating condition will be executed and recursion will end.

Exam 13: Recursion

Consider the getArea method from the textbook shown below:

Complete the following code snippet, which is intended to be a recursive method that will find the sum of all elements in an array of double values from the beginning of the array to index:

Which of the following options could be used as a terminating condition for a recursive method that finds the middle character of a String with any number of characters? i.the length of the String is 1 II.first and last String characters match III.the String is not empty

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?

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 lastIndex arguments.What statement should be used to complete the recursive method?

Consider the fib method from the textbook shown below: Computing the 7th fibonacci number, fib(7), recursively computes fib(6), fib(5), and fib(4) ___ times respectively.

Consider the method below, which implements the exponentiation operation recursively.Select the statement that should be used to complete the method so that it handles the special case correctly.

A palindrome is a word or phrase spelled which reads the same forward or backward.Consider the following code snippet: What does the method palindrome return?

A palindrome is a word or phrase that reads the same forward or backward.Consider the methods palindrome and isPal shown below: The method isPal as shown here would be considered to be a ____ method.

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

Consider the recursive version of the fib method from the textbook shown below: How many recursive calls to fib(2) will be made from the original call of fib(6)?

Would switching the special case order affect the return value of the following method?

Complete the following code snippet, which is intended to be a recursive method that will find the smallest value in an array of double values from index to the end of the array:

Consider the code for the recursive method mystery shown in this code snippet: What will be printed by the statement System.out.println(mystery(-4));?

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

Consider the method powerOfTwo shown below: How many recursive calls are made from the original call of powerOfTwo(64) (not including the original call)?

In a _____________, a set of cooperating methods calls each other repeatedly.

The method below generates all nonempty substrings of a word passed as argument.Assuming that the string contains no duplicate characters, select the statement to complete the method so that it prints all nonempty substrings correctly.

If a recursive method does not simplify the computation within the method and the base case is not called, what will be the result?

Introduction

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Fundamental Data Types

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