Programming Questions and Answers January 13, 2021

implement a software for a Coffee House using Object Oriented Programming. If you are not familiar or comfortable with objectoriented programming, we suggest you give this article a quick read to ensure you understand it before you attempt it. It should have the following features Allow users to order a coffee from Espresso, Cappuccino, Latte.

Write a C program that prints the following using goto statement, escape sequences and ASCII values of the characters shown as output. (For People who know loops already loops are strictly PROHIBITED) 5 98 a b c d g h k 1 mno pqrstu

Consider the following charging RC circuit a. Calculate the time constant. b. Find voltage across the capacitor at maximum point of steady state period. c. Find the voltage across the capacitor after 20 sec. d. How much time is needed to make the capacitor fully charged e. calculate the current. 9v Switch oto R m 3 100 F

Write a python programme in a Jupyter notebook which uses a forloop to fill an array with the first 20 Fibonacci numbers. You will need to initialise the first two elements of the array before you enter the loop. Your programme should then list the Fibonacci numbers. Finally plot a semilog graph of the numbers versus their place in the sequence.

Write a Python program that does all the following steps Read a file located in the same directory as the program named cs52155input.txt o Print a clear error message and end the program if the file is missing o The program must not crash because the file doesnt exist . Your program will have four main objectives o Determine the files length in

a. Write its Kmap. b. From such Kmap, write its minimized equation c. Draw its circuit from the equation obtained in Part b,A 0 0 0 0 0 0 0 0 1 1 1 B 0 0 0 0 1 1 1 1 0 0 INPUTS Others C 0 0 1 0 0 1 1 0 0 1 D 0 0 1 0 1 0 1 0 0 OUTPUT Y 0 1 1 0 0 0 X

Consider the following code. define N 10 int aN (1,2,3,4,5,6,7,8,9,10) int p sa0, qa N1, temp while (p

Create a class called Employee as follow public class Employee private int Id private String FirstName private String LastName private double salary public Employee(int nid, String S1, String S2, double sl) Idnid FirstName1 LastName 2 Salarys1 public string getFirstName() return FirstName public string getLastName() return LastName public int

verify the following statements. If it is truc, please show it otherwise, give an argument to show the incorrectness. (a) 2n1 O(2) (b) 22n 0(2)

Write down the truth table for these sentences 1. (BA)A (B A) 2. (BA)A (BA) 3. (BA) (BAA) 4. (BA)A (AB) A (Bv A)

14. The sequence hn is defined recursively as follows h 13 and h 25. For n 3, hn 2hn1 hn2 2 2 Use strong induction to prove the following fact about the sequence hn Theorem For any n 1, hn 2n n n3

17. Each equation below is a characteristic equation for a recurrence relation. Find the general solution for each recurrence relation. (a) (x 2)(x 4) 0 (b) (x 3)(x 3) 0 (c) (x3)(x3) 0 (d) (x 1)(x 2)(x 5) 0 (e) (x 1)(x 7) 0

13. Write the output of the following code for i in range(0,5) if i20 for j in range(0,5) if j20 print(1,end) elif j20 print(0,end) print() elif i20 for j in range(0,5) if j20 print(0,end) elif j20 print(1,end) print(),13. Write the output of the following code for i in range(0,5) if i20 for j in range(0,5) if j20 print(1,end) elif j20

Write a proof which reduces the conclusion (ry) V ((IV 2) V (y V z)) to premises that cant be reduced further. Expressions like (Ay) V ((TV2) V (y V z)) used in the antecedents and succedents of sequents are called tautologies when is valid (the antecedent is empty) 4 contradictions when is valid (the succedent is empty) Is (x Ay) V ((2 V 2) V (y

(8) Write a function called vectorVolume (x1, x2, x3) that calculates and returns the volume of a parallelepiped created by three vectors (in 3D). Use the formula V a (bx c) for three numpy arrays, a, b and c. There is also a hidden, invisible test which covers different input data.

Consider the following comparison instruction CMP r0, r1 r0 0xD95F0057, r10x8A00F342. a) Determine the value of the condition flags (N, Z, C, V) after the instruction is executed. b) From the condition flag bits found in part (a), determine which of the following conditional branches will be executed BEQ (branch if equal), BGT (branch if signed

Create a SQL query to display the combined customer name, employee id, delivery notes, coin ordered and invoice number. In your query only display the results that have any invoice date from 18th May 2021. Sample Output CUSTOMER Lucy, Williams Julien, Hendricks Sam, Clark EMPLOYEEID emp103 emp105 emp105 DESCRIPTION Delivery to work address Double

Consider the AVR statements in r20, 0x00 andi r20, 20 out 0x05, r20 Complete the following C statement so that it is equivalent to the code above. 20

Demonstrate your understanding of memory system by designing a basic ARM memory system with the following information An ARM memory system has 4 physical 4Kx8 EPROM memory located at 0000h. There are also 4 physical 4Kx8 RAM memory modules. The RAM module starts from C000h. (i) Sketch the memory map of the system. (ii) Sketch the memory system

1. Write a function MyTrapezoidQuad that takes as inputs a function f and an array of values xs with spacing h between them. The function should return the approximated integral of f over the interval (zo...) using the trapezoid rule on the given points. Hint Use the pseudocode in Listing 1 to write your function. Use your Matlab function to

Consider the following fragment of code n 0 a d x d m What do a, b and c statements represent a b 0 X 0 x d m b while (d n) do X X m d d 1 C Complete expression c replace by its value et deduce the final expression of c

Suppose that you have the following knowledge base Physicists and gelogists are scientists. Vx((Physicist(x) V Geologist (x)) Scientist (x)) All geologists work for Exxon or Shell. Vx(Geologist (x) (Worksfor(x,Exxon) V Worksfor(x, Shell))) No physicists work for Exxon or Shell. Vx(Physicist (x) (Worksfor(x, Exxon) AWorksfor (x,Shell))) If a

The Turing machine we encountered in class has the transition function, della(Qx1) Qxrx (L, R. Consider a variant of a Turing machine whose transition function is, 8(Qx1) QxIx (L, R,S, where S indicates that the head stays at its current location. Prove that this variant is no more powerful than the original, i.e. the set of languages accepted

Write a C++ program name: Horse Race Write a program that runs a random horse race. The specification: There are three horses. During each round, a random number from 1 to 100 is generated for each horse. The horse advances one length if the random number is greater than 50. My track is 15 lengths long. Show the track this way: 1|--------H------|

4. Read the threeintegers from the command line window Evaluate the Pell equation X Y n 3 2 1 f(x, y, n)x nx y Print out the result in the command line window. At the end of the problem clearly state the result (decimal) . In the report include a screenshot of the console with the result.

Write a program to drill elementary school students on addition, subtraction, multiplication or division. 1. The program must allow students to: select an operation from a menu (see example in sample output below), practice 5 randomly generated problems of that type using whole numbers between 0 and 20 (inclusive), and keep score of the

) Briefly explain what the following function is doing fun foo 11 12 foldl (fn (hd, acc) if (exists 12 hd) then acc else hd acc) 11 foo a list a list a list assuming that function exists is defined as fun exists n false I exists (xxs) n if n x then true else exists xs n For example, what is the result of foo a,b, c b, c

You have been assigned to design a16M Byte memory board out of256K Byte chips. Each time an access is made to the memory two bytes are returned. Thus, the memory is half-word addressable. Each of the256KB chips is byte addressable. Assume address multiplexing is not used (Similar to the example in slide4/22.Use the example in slide4/22as a guide

Write a menu driven program in python that does the following: This program requires you to create a menu driven program that will generate invoices for veterinary services until the user quits. When a service is selected, display an appropriate message as shown below (you may choose your own appropriate message). The program

3. Write a program that receives two alphabet letters and count the number of vowels (a, e, i, o, and u) between them. Enter the first letter u Enter the second letter E Number of vowels 3 Assume that the user may enter both uppercase and lowercase letters. The alphabet letters are ordered from A to Z and from a to z. Z is followed by the letters

Why is the output of this code 1 1 1 1 1 1 ? 1 public class Test { 2 public static void main(String[] args) { 3 int list[] = {1, 2, 3, 4, 5, 6}; 4 for (int i = 1; i < list.length; i++) 5 list[i] = list[i - 1]; 6 7 for (int i = 0; i < list.length; i++) 8 System.out.print(list[i] + " "); 9 } 10 }

1. Given the following truth table, find the corresponding Boolean expression F. A 0 0 0 0 1 1 1 1 . B C 0 0 0 1 1 0 0 1 1 0 1 1 1 1 1 0 1 0 1 F 0 Sketch the Karnaugh Map for this function. (2 marks) Using the Karnaugh Map, get the simplest sumofproducts form for this function. Show your full work (circling the necessary 1s). (3 marks) Draw the

2. Let U 0,1,2,3,4,5,6,7,8,9,10), A 0, 2, 4, 6, 8, 10), B 0, 1, 2, 3, 4, 5, 6) and C 4, 5, 6, 7, 8, 9, 10 Evaluate and show all your work. (2 marks each) a. (AUC) b. A B c. AB

For binary antipodal signaling, determine the average necessary SNR per bit (EbNo) to achieve a probability of error (P) no greater than 105. Likewise, for binary orthogonal signaling, determine the average necessary SNR per bit to achieve the same Pe. Note that we have Q(105) 4.2649, or equivalently Q(4.2649) 105. Note For binary antipodal

Use MATLAB to solve the following Consider the random variable X (Ui 12) 12 i1, where the Uts are uniform random variables. 6.1 Write a MATLAB code to estimate (use 1,000 trials) the PDF (probability distribution function) of X and to compute the Gaussian PDF px(x) 1 2e 12x2. 6.2 Plot the estimated PDF and overlay the Gaussian PDF plot. Submit

P3. What are the compiled MIPS assembly codes a) g h A 20 b) (5205) A is an array of 100 words and that the compiler has the associated the variables g and h with the registers s1 and s2.Also the base address of the array is in s3. int leafexample (int g. int h. int i, int j) int f f (g h)(1 5) return f The parameter variables g, h, i, and j

4) Write a C program that inputs five numbers from user and determines and displays the number of negative numbers input, the number of positive numbers input and the number of 0 input. 1 mark 5) Write a C program to perform to demonstrate the error handling using Try, catch and finally block. 1 Marks 6) Write a C program to create a BMI

Write a C program in Windows Form to calculate Zakat amount for the given amount. Hint Enter the amount in textbox, then it should give zakat amount by calculating Enter amount value x 0.25 in message box 2.5 Marks Zakat Calculator Enter Amount Calculate Zakat X

Write an algorithm in pseudocode to insert an element into a sorted array. The algorithm must call a search algorithm to find the location for insertion.

Suppose we have the following array a int a new int 7, 22, 19, 56, 10 7 0 22 1 19 56 2 3 We then execute the following lines of code Int b b a.clone() b2 0 What will be the value of a2 10 4

2. Write a complete C program that does the following Prompt the user for two positive integers. The difference in value between the two integers must be at least 10. For example . 9 and 15 would be invalid inputs because 15 is only 6 more than 9. 14 and 25 would be valid inputs because the difference between the two is 11, which is greater than

Write a C code to read one integer (M) followed by another two integers (i, j). Display the ith through the jth digits of M. For example if the inout is 1234567 14 Display digits 1 through for of the integer 1298567 Integer 1 2 9 8 5 6 7 Digit number 6 5 4 3 2 1 0 So you must display digits 1 through 4, i.e. display 9856 Hint Read as integer, not

1. Consider the following polynomial y 2x9x 2 Create a userdefined function called polynomial that accepts x value as an input and returns the y value of the polynomial. Use the function polynomial to calculate the y value when the user enters a value for x. 2. A rocket is launched vertically. The height of the rocket as a function of time is

A system adopts the Preemptive-Priority scheduling wherein the Arrival Time, Burst Time and priority for each process has been shown in the table below. In a recorded time-span, the system has six processes, P1, P2, P3, P4, P5 and P6 as shown in the following table. At time t=15, the process running will ask for some I/O. The I/O operation takes

2. Complete the following questions related to Bracket methods (a) Write a function to perform the Bisection method for any scalar nonlinear equation f(x) 0. The inputs to your function should be a function that calculates the nonlinear equation, the endpoints of the bracketing region, a convergence tolerance and a maximum number of iterations.

3. Compute the value of the following expressions. Give the smallest positive value for each an swer. Show your work (i) 343 mod 5 (ii) 72 (65) 211) mod 7 (iii) 5873 mod 7

13. Arrange array3 in ascending order using Selection sort. Show all steps. (5 marks) int array3 (3, 5, 7, 1, 2) I 14. Arrange array4 in ascending order using Insertion sort. Show all steps. (5 marks) int array4 7, 4, 3, 2, 8)

Write a bash script that creates an array of shapes square, rectangle, triangle, and circle. The script prompts the user to enter to select one of these shapes. Based on the shape, it should prompt the user for the necessary value to calculate the area of the shape selected. The script should then display the value calculated. (Use 3.14 for pi)

1. Briefly describe questions below A. What is a normalized floating point number and what is the purpose of normalization B. A general floating point system is characterized by four values (P. 1, L, U). Explain in a few brief sentences the meaning and importance of each of these parameters. C. Write down the floating point representation of a

In the following Bayesian Network, B, E, A, J, and M denote binary probability variables which denote Burglary, Earthquake, Alarm, John's Call, and Mary's Call, respectively, and b, e, a, j, and m represent the events which actually happen (i.e. true events), respectively. Calculate (answer and process) the following probabilities: 1) P(m|b) 2)

J P(B) 0.01 A P(J) .90 .05 f A E BE t t f f t f t f M P(E) 0.02 P(A) .95 .85 .25 .01 A t f P(M) .80 .02

A bank manager has n clients waiting to be served, all of whom arrived at the same time. Let us call the time at which these clients arrive to be 0. The manager estimates that client i requires t time units of service. They also know the clients well and assign each client a weight according to how important the client is to the bank (say, the

3. Determine the best bound for the following codes running time using BigO notation 2 5 i) for (i0 i

Write a C Program that generates a triangular wave and displays it on the UAH Serial app (using a 57,600 baud connection). The parameters for the triangular wave are as follows: (a) Amplitude 9 Units. (b) Frequency: 4 Hz. This signal will be transmitted to the serial app for a duration of 6 signal periods. Example output is shown below.

0 500 Time ms 1000 1500 10 8 6 2 0 Amplitude

1. Starting with array S 123, 34, 89, 56, 150, 12, 9) indexed from 1 to 7 a) (15 pts) Sort S using Merge Sort. Show the recursive tree and indicate order of execution, i.e., label steps in tree nodes. b) (5 pts) For n 32, in the best case Merge Sort would be expected to perform how many comparisons

Write a program in Hack VM code to multiply 2 numbers a x x y. Complete the code in Mult.vm Where a is a local variable x y are both static variables (supplied in that order) You are required to implement the multiplication algorithm yourself solutions using the inbuilt Math function will not receive marks.,1 2 AWN 3 4 5 Put your code here.

3. Consider the binomial expansion of (a b)0 wihtout resorting to computing factorials. a) (10 pts) Find the value of the coefficient of the term ab in the above binomial expansion without resorting to computing factorials. Show your work. b) (5 pts) True or False In the topdown Divide and Conquer algorithm for computing binomial coefficients,

4. For a certain directed graph with 4 vertices, Floyds Algorithm has produced the following arrays D(3) and P(3). Using these values, compute the missing values in the arrays D(4) and P(4), Show how you computed. D(3) 1 2 3 4 1 0813 2 16 0 7 9 9 17 0 2 6 3 7 0 3 4 a) (3 pts) D4 1 2 b) (3 pts) D(4)23 c) (3 pts) P(4) 2 3 d) (3 pts) P(4) 32 P(3)

Given an array 19, 95, 48, 96, 33, 52, 17, 23, 69, 42 and a gap value of 2 What is the first interleaved array Ex 1, 2, 3 (comma between values) What is the second interleaved array

5. For the 01 Knapsack Problem, the item 1 has weight of 4 and the value of 12 the item 2 has weight of 1 and the value of 1 the item 3 has weight of 5 and the value of 10 and the item 4 has weight of 2 and the value of 8. The capacity of the knapsacks weight is 10. The Dynamic Programming algorithm has produced the following array. Fill the last

Develop a Java program that meets the following requirements: Assume that you are developing video game code in Java, and the main character must encounter a sequence of randomized experiences. The experiences will be stored in a tree data structure, and the character will begin at the experience in the root node of the tree. The character will

Write a paper explaining the process of identifying stakeholders, how to create a stakeholder register, and how to perform a stakeholder analysis.

3. a. For setAssociative mapping if Main Memory 64GB, BlockLine Size 16B, Cache512 KB with 4 way set associative 4 i. How many address bits are required to address each byte location in RAM ii. How many main memory blocks are there iii. How many cache lines are there iv. How many cache lines per set are there v. How many cache sets are there vi.

3. Consider the following grammar ( ) x yzp Write the lefthand derivation and draw the parse tree for (xy z) p

d. Find out tagsetword bits for memory address 2B8A9CH for twoway set associative (Assume cache memory size 64 KB, number of bytes in each line is 8 bytes, and memory size is 64MB). 2 1 e DRAM multiplexed addressing plus the use of square arrays result in ii. i. tripling of memory size with each new generation of memory chips doubling of memory

2. a. Write two separate programs to solve the following problems weight Convert a weight in kilograms to its equivalent in pounds or convert a weight in pounds to its equivalent in kilograms. Write a program to input a weight and then choose which of the two calculations to do and then calculate and print the answer. You can assume there is no

1. What does the following recursive function do, in general bool Mistery (char s, int low, int high) if (high y) return (x y) else return fun (x 1, y 1) What is the output of the following statements a. cout fun ( 7, 12) b. cout fun (4,8) 3. Consider a function, power, that takes as parameters two integers x and y such that x is

Write a Python function called sumUntilEven that takes in one parameter, Ist, and returns the sum of all the elements in the Ist up to but not including the first even number. For example, sumUntil Even(1,2,3,4,5 should return 1 and sumUntilEven (1,3,5,7,9 should return 25.

Create a Python function called sumOf Odds which takes one argument, an integer greater than or equal to 1, and returns the result of adding the odd integers between 1 and the value of the given argument (inclusive). This function does not print. Do not use Pythons sum () function. Do not build a list. You may assume that the argument is valid.

4.) Write a Python function called sum5powerlist which takes one argument, a list of numbers and which when invoked by sum5powerlist (listofnumbers) will print out AND return the sum of the fifth powers of each the numbers in the list. Test cases sum5powerlist (1) should print 1 because 15 1 1 1 sum5powerlist (1,2) should print 33 because 15

Write a program to print the following pattern. The s must be printed using only loops (no more than two).

Create a function called encoder which expects two arguments. The first argument is a string representing a message to be translated into a coded message. The second argument is a list of lists serving as the key to be used to convert the original string to its coded equivalent. Each twoelement list in the key represents a character that might be

The following figure depicts a circular doubly linked list with current being a pointer to one of its nodes. Let node be a struct consisting of a char key and node next. What is printed by the following code segment node forward current current backward node do ( cout forwardkey cout backwardkey forward forwardnext backward while (forward 1

What is the output of the following C code int a 3, b 5 float c 3.2, d 1.8 a b c c2a2 d d2 2 (b2) cout d d endl

An investors wealth dynamics is given by the following Xt1 UfWt where w is an i.i.d. positive, Rvalued, stochastic process. The investor has access to the past and current wealth information and his actions. The goal is to maximize J(xo II) T1 Erolb(x ut) t0 The investors action set for any given x is U(x) 0, x. Formulate the problem as an

What is the output of the following C code int x 10 int y 20 if (x 10 y 20) x 2 x yy2 cout y x y endl else xyx yxy cout x

Write a SQL statement that will list for each customer whose billing address is on a road the customers first name, the customers last name, and how many orders the customer has placed. Use first name, last name, and numb orders for the column headings. ww www m,addresses addressid INT customerid INT line 1 VARCHAR(60) line 2 VARCHAR(60) city

Follow the individual instructions for each of the exercises below. Each questions point value is given in the prompt. 1. 5pts Write a program that asks the user to enter a persons age. The program should display a message indicating whether the person is an infant, a child, a teenager, or an adult. The parameters for each classification are given

Imagine that you are writing a program for a software company which sells a product that retails for 99, but are discounted at certain quantities according to the following table Quantity Sold 1019 2049 5099 100 Write a program that asks the user to input the number of products sold, then returns the total cost of their purchase along with how

Write a program that prompts a user to enter the average speed of a vehicle traveling and the time which it traveled. The speed should be given in milesperhour (MPH) and the time should be in hours. Once entered, the program should calculate the distance traveled at EACH hour of the vehicles journey. The output should look something like this What

Write a MIPS Assembly code to find the first and third element of the following array (50 Define an integer array that contains 17, 12, 15, 27. Print the first and third element of this array. Points). Question 2 Write a MIPS Assembly code to find the maximum number from a list of 10 whole numbers, then print the max value to screen (50 Points).

Write the plain English for the following SQL statement SELECT p.product name FROM products p JOIN order items oi wwwwww ON p.product id oi.product id GROUP BY p.product name HAVING COUNT()

What is the output of the following C code const int SECRET 3 int w0, x6, y10, z20 if (z 10) y z else x Z w y SECRET (y x ) cout Result is Z W endl

3. Create an abstract class named Person. This abstract class is composed of the following instance variables and methods (8 marks) Instance variables name, and contact number Constructor initialize name and contact number based on value from parameters Concrete method accessor method for name and contactnumber Abstract method public void

Suppose we have a list of strings, named by L1, such as the following example L1 this, is, a, short, list Write code using a list comprehension to assign to L2 a list composed of the lengths of each of the items in L1. 1L1 this, is, a, short, list YOUR CODE HERE raise NotImplementedError() print (L2) assert L2 14, 2, 1, 5, 41 I

There are several technologies affect global society such as Al, robotics, social network etc. Explain one of them. How it affects the global society Give examples. Question 2 (50 points). Each revolution (agricultural, industrial) in the history impacted the life style of people. As we go through a new revolution (artificial intelligence,

Creating data and looping through it a. In a for loop create a range of numbers from 1 to 5 and print them. b. Create this list 1,5,2,10,4,7 and find the cube root of every number in that list in a for loop. Append the result to a list called croot. c. Write a for loop such that it prints every alphabet in the string

Write a program to convert a list of numbers into its squares For this question, use a for loop first (as one way), and list comprehension (as the second) original (1, 2, 3, 4, 5, 6, 7) for loop 1, 4, 9, 16, 25, 36, 49 list comprehension 1, 4, 9, 16, 25, 36, 49) Concatenate two lists in the following order 1.3 (5 points) Concatenate two lists in

Given a dictionary of students name with their assigned values students student1 13, student2 17, student3 9, student415, student58, student6 14, student7 16, student8 12, student9 13, student10 15, student1114, student1129, student 13 10, student 14 12, student1513, student167, student 17 12, student1815, student199, student2017),Write a

P2. Based on the Table below, Activity ABCDEFGHI I (End) Immediate Predecessor 111 A A B B,C D E,F G, H, I Time (days) 8 20 33 18 20 9 10 8 4 a) Construct AOA and AON network diagrams. b) Perform the forward and backward pass analysis on the AON diagram. Indicate the critical path. c) What is the duration of the project d) Calculate the total

Consider the data in the unordered list shown below (7, 1, 65, 43, 76, 55, 12, 8, 22, 13, 74, 71, 2, 9, 98) A swap sorter algorithm is used to sort this data into ascending order with the smallest value on the left and the largest on the right. a) Write down the sequences produced by the first two iterations of this sorting algorithm. 2 marks b)

A bubble (swap) sorter is used to sort 100,000 words for an English language dictionary application. a) Show that the number of swaps required to sort N words in a dictionary is approximately N. 1 mark b) A student measures that a swap operation takes 0.01 ms on an old piece of hardware. Ignoring all other computing overheads, exactly how long

Use 3 perceptron to implement XOR. X, Y, Z 0,1 1. Specify the 4 weights of the first layer Wx1, Wx2, Wy1, Wy2, 2. Specify the 2 weights of the second layer W, W 3. bias of the first layer and second layer b1 and b2. 4. Specify what activation function you use. X Y W N

Which initial value of number would cause an infinite loop REPEAT UNTIL (number number number 1 0) Any positive integer. Any negative integer. Any even integer. Any odd integer.

Modify mybisect to solve until the absolute error is bounded by a given tolerance. Use a while loop to do this. Run your program on the function f(x) 2r 3x1 with starting interval 0, 1 and a tolerance of 108. How many steps does the program use to achieve this tolerance (You can count the steps by adding 1 to a counting variable i in the loop of

statement Use the method of proof using the contrapositive to prove the following For all integers p, q and r, if r X (2p5q) or r X 3pq, then r Xp or r Xq Reminder the notation means does not divide. Write a formal proof for the following biconditional statement. For all integers x and y, 5xy is even if and only if x is even or y is even. Hint For