Test #2 October 8, 2015

Size: px

Start display at page:

Download "Test #2 October 8, 2015"

Alexander Gibbs
5 years ago
Views:

1 CPSC 1040 Name: Test #2 October 8, 2015 Closed notes, closed laptop, calculators OK. Please use a pencil. 100 points, 5 point bonus. Maximum score 105. Weight of each section in parentheses. If you need more space, use the back of the sheet. A. (20 points) Multiple Choice. Circle the best answer. 1. Multiple Boolean expressions can be combined by using a logical operator to create expressions. a. sequential b. logical c. compound d. mathematical 2. When using the operator, one or both subexpressions must be true for the compound expression to be true. a. or b. and c. not d. maybe 3. Which logical operators perform short-circuit evaluation? a. or, not b. not, and c. or, and d. and, or, not 4. A Boolean variable can reference one of two values:. a. yes or now b. true or false c. T or F d. Y or N 5. What is the result of the Boolean expression: x < y or z > x if x equals 5, y equals 3, and z equals 8? a. true b. false c. 8 d What is the result of the Boolean expression: x < y and z > x if x equals 5, y equals 3, and z equals 8? a. true b. false c. 8 d What is the result of the Boolean expression: not (x<y or z>x) and y<z a. true b. false c. 8 d Which of the following is the correct if clause to use to determine whether choice is other than 10? a. if choice!=10: b. if choice!=10 c. if choice<>10: d. if choice<>10 9. When using the operator, both subexpressions must be true for the compound expression to be true. a. or b. and c. not d. maybe 10. In Python, the symbol is used as the not-equal-to operator. a. == b. <> c. <= d.!=

2 11. In Python the symbol is used as the equality operator. a. == b. <> c. <= d.!= 12. What are the values that the variable num contains through the iterations of the following for loop? for num in range(2, 9, 2) a. 2, 3, 4, 5, 6, 7, 8, 9 b. 2, 5, 8 c. 2, 4, 6, 8 d. 1, 3, 5, 7, is the process of inspecting data that has been input to a program to make sure it is valid before it is used in a computation. a. Input validation b. Correcting data c. Data validation d. Correcting inut 14. The first input operation is called the, and its purpose is to get the first input value that will be tested by the validation loop. a. priming read b. first input c. loop set read d. loop validation 15. What is the structure that causes a statement or a set of statements to execute repeatedly? a. Sequence b. Decision c. Module d. Repetition 16. When will the following loop terminate? while keep_on_going!= 999 : a. When keep_on_going refers to a value less than 999 b. When keep_on_going refers to a value greater than 999 c. When keep_on_going refers to a value equal to 999 d. When keep_on_going refers to a value not equal to In Python, a comma-separated sequence of data items that are enclosed in a set of brackets is called a. a. sequence b. variable c. value d. list 18. Which of the following represents an example to calculate the sum of the numbers (accumulator)? a. total + number = total b. number += number c. total += number d. total = number 19. Which of the following statements causes the interpreter to load the contents of the random module into memory? a. load random b. import random c. upload random d. download random 20. Which of the following will assign a random number in the range of 1 through 50 to the variable number? a. random(1,50) = number b. number = random.randint(1, 50) c. randint(1, 50) = number d. number = random(range(1, 50)

3 B. (25 points) True or False. Circle the correct answer. 1. True/False: The if statement causes one or more statements to execute only when a Boolean expression is true. 2. True/False: The Python language is not sensitive to block structuring of code. 3. True/False: Python allows you to compare strings, but it is not case sensitive. 4. True/False: Nested decision structures are one way to test more than one condition. 5. True/False: Python uses the same symbols for the assignment operator and the equality operator. 6. Free Bonus 7. True/False: Short-circuit evaluation is performed with the not operator. 8. True/False: Expressions that are tested by the if statement are called Boolean expressions. 9. Free Bonus 10. True/False: An action in a single alternative decision structure is performed only when the condition is true. 11. True/False: Both of the following for clauses would generate the same number of loop iterations: for num in range(4): for num in range(1,5): 12. True/False: The integrity of a program s output is only as good as the integrity of its input. For this reason the program should discard input that is invalid and prompt the user to enter correct data. 13. True/False: Functions can be called from statements in the body of a loop, and loops can be called from the body of a function. 14.True/False: In a nested loop, the inner loop goes through all of its iterations for every single iteration of an outer loop. 15.True/False: The function header marks the beginning of the function definition. 16.True/False: A local variable can be accessed from anywhere in the program. 17.True/False: Different functions can have local variables with the same names. 18.True/False: Python allows for passing multiple arguments to a function. 19.True/False: The value assigned to a global constant can be changed in the mainline logic. 20. True/False: One of the reasons not to use global variables is that it makes a program hard to debug. 21. True/False: A value-returning function is like a simple function except that when it finishes it returns a value back to the called part of the program. 22. True/False: Boolean functions are useful for simplifying complex conditions that are tested in decision and repetition structures. 23. True/False: In Python, one can have a list of variables on the left side of the assignment operator. 24. True/False: In a menu-driven program, a loop structure is used to determine the menu item the user selected. 25. True/False: The math function, ceil(x), returns the smallest integer that is greater than or equal to x.

4 C. Python Programming (20 points) 1. (10) Consider the following Python function. Then answer the questions below. def mystery(n): if (n < 1 or n > 10): result = "Bad input. Please enter an integer (1 <= n <= 10)." elif (n >= 4): result = "V" if (n>=9): result = "X" if (n==9): result = "I" + result elif (n==4): result = "I" + result else: for count in range (1,n-4): result += "I" else: result = "" for count in range (1,n+1): result += "I" return result What is printed by the Python statement: (a) print(mystery(3))? (c) print(mystery(8))? (b) print(mystery(4))? (d) print(mystery(9))? (e) Give a general statement about what the function mystery() returns. 2. (5) Complete the Python function shown below called comparerectangles()where length1 and width1 hold the length and width of rectangle 1 and length2 and width2 hold the length and width of rectangle 2. The function should return a result of 0 if the areas of the two rectangles are equal, a 1 if the area of rectangle 1 is greater than the area of rectangle 2, and a 2 if the area of rectangle 2 is greater than the area of rectangle 1. You do not need to include comments. Your code should be syntactically as well as logically accurate. The function has been started for you. def comparerectangles(length1, width1, length2, width2): return result

5 3. (5) Complete the Python function called multiples() shown below. The function should print the multiples of the argument n starting with n up to and possibly including For example, and multiples(5)should print: multiples(3)should print: The function has been started for you. def multiples(n): D. Useful Formulas. (20 points) Simplify each of the following. Use G, K, T, Z, M, P, Y and E as appropriate. Show clearly how you arrived at your answer. All logarithms are base 2. You may use a calculator. 1. log ((A Z * B X ) / (E Y * W D )) = = = 4. ((2 50 )/ (32M)) * (2 15 ) / ((2 19 )*(256K)) = 5. ((P/M*K)/(G*Z/T))*2 35 =

6 E. (15 points) Permutations and Combinations. Show clearly how you arrived at your answers. 1. How many permutations of 5 different digits are there, chosen from the 26 letters A through Z? 2. If 100 people shake hands so that each person shakes every other person s hand exactly once, how many handshakes take place? 3. A password consists of two letters of the alphabet followed by two digits chosen from 0 to 9 followed by three letters of the alphabet. Repeats are allowed. How many different possible passwords are there? F. (5 points) Bonus Question. Consider the activation record stack shown below left. Assume that the letters A, B, C, D, and E represent Python functions. Then answer the questions below. Which function is currently in control? A D Which function resumes control after function D completes execution? C B Which function started the execution process? E Which function does function C call? When function completes execution, the Python program terminates.

5.1. Chapter 5: The Increment and Decrement Operators. The Increment and Decrement Operators. Looping. ++ is the increment operator.

5.1. Chapter 5: The Increment and Decrement Operators. The Increment and Decrement Operators. Looping. ++ is the increment operator. Chapter 5: Looping 5.1 The Increment and Decrement Operators Copyright 2009 Pearson Education, Inc. Copyright Publishing as Pearson 2009 Addison-Wesley Pearson Education, Inc. Publishing as Pearson Addison-Wesley