Programming Quiz on Loops and Data Types

Question 22

• The code fragment uses a for loop with a range of 20 to 9, stepping by -1
• This means the loop will iterate 11 times (20, 19, 18, ... 10, 9)
• The loop prints "exam" in each iteration
• Therefore, the word "exam" will be printed 11 times

Question 23

• ["hello", "again"] is classified as a list data type
• (2,3) is classified as a tuple data type
• "hello" is classified as a string data type

###‌ Question 24

• The function function(lst) is recursive, calling itself with a smaller sublist
• The base case is lst == [] (an empty list), which returns 1
• When lst is not empty, the function recursively calls itself with lst[1:] (removing the first element)
• It then calculates a * function(lst[1:]) * math.sqrt(16)
• After three recursive calls, the function returns 1 * 4 * 4 * 4 which equals 64
• In this case, the math.sqrt(16) is irrelevant since it's constant

Question 25

• foo2(2) returns 1 + 2 = 3, which is used in foo1()
• foo1() returns 3
• whatisthis(2) returns 3 + 2 = 5
• foo2(2) returns 1 + 2 = 3
• Therefore, whatisthis(2) + foo2(2) evaluates to 5 + 3 = 8

Question 26

• f1(x) calls f2(x-1) unless x is 0, which returns True
• f2(x) calls f1(x-1) unless x is 0, which returns False
• f1(5) calls f2(4), which calls f1(3), which calls f2(2), which calls f1(1), which calls f2(0)
• f2(0) returns False and propagates back through the function calls until f1(5) returns False

Question 27

• The purpose of the code is to check if a number x is a prime number (divisible by 1 and itself only)
• CODE_A should be x % c (the remainder of x divided by c) to check for divisibility
• CODE_B should be False to return False if x is divisible by any number other than 1 and x
• CODE_C should be True to return True if x is not divisible by any number within the loop

Question 4

• The function should count the number of clouds in the clouds list that have a width greater than 5
• The base case is an empty list (clouds == []), which returns 0
• When clouds is not empty, it checks if the width of the first cloud is greater than 5
• If yes, it should increment a counter and call itself recursively with the rest of the list (clouds[1:])
• If no, it directly calls itself recursively with the rest of the list (clouds[1:])

Question 5

• The augmenting recursion version took the longest time to run for fibonacci series

Question 6

• The function has a recursive call within the while loop
• The base case is time == endOftime-1, which returns -1
• In the code above, endOftime is set to 999, and time starts at 0
• The while loop keeps executing until time reaches 998 (endOftime - 1)
• When time reaches 998, the base case is hit, and -1 is returned

Question 7

• The function iterates through the list elements with a for loop
• The function returns the length of the list after the loop
• The if conditional (el == 0) is never satisfied since the list is [1,2,3,4,5]
• The loop does nothing, and len(lst) returns 5

Question 8

• The function returns w = 50
• This is incorrect because the = operator is used for assignment, not comparison
• The code will assign w to 50 and then return w, but it won't check if w equals 50.
• Therefore, evaluating pass_grade(50) will return 50, not a boolean value

Question 9

• The function calculates the number of digits in a number
• The count(number, total) function uses recursion to check each digit
• The base case is when number is less than 10. In this case, the function returns total directly
• Otherwise, it calls count recursively with number // 10 and total + 1, iterating through the digits
• The digits(number) function initializes the total to 0 and calls count to begin the digit counting process

Question 10

• mylst[:4] returns a slice of the list from the beginning up to, but not including, index 4, which is ["COMP1126",[0,1,2,3,4,5,6,7], [], [[1,2,3]]]
• mylst returns the entire list ["COMP1126",[0,1,2,3,4,5,6,7], [], [[1,2,3]]]
• mylst[-1] returns the last element of the list, which is [[1,2,3]]
• mylst[2:-1:2] returns a slice of the list starting at index 2 up to, but not including, the second-last element, taking every other element, which is [ [], [[1,2,3]] ]

Question 11

• CODE_A should be path[0] (first element of path) which represents the starting location X
• CODE_B should be and to check if both starting and ending locations match the X and Y of the path
• CODE_C should be path[2] (third element of path) to return the time between the locations

Question 12

• The function has a logical error
• if (a = c) ... is not a valid comparison in Python, it assigns a to c
• Since a is being assigned in the if condition, a will always be equal to c, leading to an infinite loop and the function never returning a value
• The or condition also has the same error, which is why the function never returns a value

Question 13

• There is no code in the Question to provide a base case
• The code uses base cases to prevent infinite recursion in the if statements (e.g. if x == 0 )

Test your knowledge of Python programming concepts with this quiz focused on loops, data types, and recursion. Determine how various data structures are used and how functions behave under certain conditions. Challenge yourself and see how well you understand these key concepts!