2. What are the two main components to the CPU and what do each of them do? 3. What is the difference between a compiler and an interpreter?

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1 COSC 117 Exam 1 Key Spring 2011 Part 1: Definitions & Short Answer 1. What do CPU and ALU stand for? CPU Central Processing Unit ALU Arithmetic and Logic Unit 2. What are the two main components to the CPU and what do each of them do? The CPU consists of the ALU (Arithmetic and Logic Unit) and the Control Unit. The ALU does the calculations and the Control Unit controls the running of the program. 3. What is the difference between a compiler and an interpreter? A compiler will take a program written in a high-level language, translate it into machine language and then save the machine language program to a file that can be run on the computer. An interpreter does essentially the same thing except that it translates the high-level language to machine language one command at a time and does not save the machine language program to a file. 4. What are the four basic types of instructions and the two basic types of control instructions? 1. Assignment 2. Read 3. Write 4. Call to a procedure 5. Conditional statement 6. Loop 5. In object oriented programming, what are the states and what are the methods? States are the attributes of the object, data that the object stores, and methods are the actions you can do on the object.

2 Part 2: Program Traces 1. For each of the program inputs below write the output of the program. public class Exam1Trace1 { System.out.print("Input x: "); double x = keyboard.nextdouble(); System.out.print("Input y: "); int y = keyboard.nextint(); double z = 3*x-y/2; double w = Math.pow(x, y); System.out.println(x + " " + y + " " + z + " " + w); (a) Input x: 1 Input y: (b) Input x: 2 Input y: (c) Input x: 4.1 Input y: (d) Input x: 4 Input y: 2.4 RUN TIME ERROR

3 2. For each of the program inputs below write the output of the program. public class Exam1Trace2 { System.out.print("Input x: "); int x = keyboard.nextint(); System.out.print("Input y: "); int y = keyboard.nextint(); (a) (b) (c) (d) (e) if (x-y < 0){ System.out.println(y + " is larger than " + x); else if (x+y > 10){ System.out.println((x+y) + " is greater than 10"); else if (y > 0){ System.out.println(y + " is positive"); else if (x < 0){ System.out.println(x + " is negative"); else { System.out.println("None of the above. "); Input x: 5 Input y: 6 6 is larger than 5 Input x: 0 Input y: 0 None of the above. Input x: -6 Input y: -6-6 is negative Input x: 17 Input y: is greater than 10 Input x: 1 Input y: 1 1 is positive

4 3. For each of the program inputs below write the output of the program. public class Exam1Trace3 { System.out.print("Input n: "); int n = keyboard.nextint(); (a) (b) (c) (d) (e) while (n > 0){ if (n % 3 == 0){ n = n/3; else if (n % 10 == 0){ n += 2; else if (n % 2 == 0){ n = n/2; else { n--; System.out.print(n + " "); Input n: Input n: Input n: Input n: Input n:

5 4. The following is an Alice program that has two objects in the world, Socrates and a Snowman. There are also two numeric variables n and ThingNumber. If the user inputs the numbers 4 then 1 then 3 then 0 what will the program display? Be explicit on what things happen together and what happens in order. world.my first method ( ) ThingNumber = 1, n = 1 Do in order While ( ThingNumber > 0 ) ThingNumber set value to ( ask user for a number question = Enter a Number: ) If ( ThingNumber < 2 ) Else Do together Do in order socrates move left 0.5 meters socrates move right 0.5 meters Do in order snowman resize 2 snowman resize 0.5 n set value to ThingNumber While ( n > 0 ) Do together snowman turn left 1 revolution socrates turn right 1 revolution decrement n by 1 Input 4: Socrates and the Snowman rotate in opposite directions four times and they rotate at the same time. Input 1: Socrates moves to the left ½ meter and at the same time the Snowman increases in size by a factor of 2. Then Socrates moves to the right ½ meter and at the same time the Snowman returns to his normal size. Input 3: Socrates and the Snowman rotate in opposite directions three times and they rotate at the same time. Input 0:Socrates moves to the left ½ meter and at the same time the Snowman increases in size by a factor of 2. Then Socrates moves to the right ½ meter and at the same time the Snowman returns to his normal size. Then the program ends.

6 Part 3: Coding 1. Write a program that will ask the user to input their first name, last name, and year of birth (in yyyy format, such as 1985). The program should calculate their age and then print out the users formal name (like Doe, John) followed by their age. Then if the user's age is less than or equal to 12 print out You are just a kid., if the user's age is greater than 12 but less than 20 then print out You are a teenager., if the user's age is greater than or equal to 20 but less than 30 then print out You are getting up there., and finally if the user's age is greater than or equal to 30 print out Man, you are old!. public class Exam1Prog1a { System.out.print("Input First Name: "); String first = keyboard.next(); System.out.print("Input Last Name: "); String last = keyboard.next(); System.out.print("Input Year of Birth (yyyy): "); int year = keyboard.nextint(); int age = year; System.out.println(last + ", " + first + " Age: " + age); if (age <= 12){ System.out.println("You are just a kid."); else if (age < 20) { System.out.println("You are a teenager."); else if (age < 30) { System.out.println("You are getting up there."); else { System.out.println("Man, you are old!");

7 2. Write a program that will take as input a positive integer n from the user, that is, the input could be 1 or 2 or 3 etc.. The program should calculate and output the sum of all the numbers from 1 to n and the product of all the numbers from 1 to n. That is, n and n. The program should continually ask the user for another number until the user inputs 0. public class Exam1Prog2a { System.out.print("Input a number: "); int n = keyboard.nextint(); while (n!= 0){ int sum = 0; int product = 1; int count = 1; while (count <= n){ sum = sum + count; product = product * count; count++; System.out.println("Sum = " + sum + " System.out.print("Input a number: "); n = keyboard.nextint(); Product = " + product);

8 3. Write a program that will take an input of a positive integer number from the user, say n. Repeat the following process until n is equal to 1. If n is even replace n by n/2 and if n is odd replace n by 3n+1. The program must print out the sequence along with a count of the number of numbers in the sequence. public class NiftySequence { System.out.print("Input a number: "); int n = keyboard.nextint(); System.out.print("Sequrence: " + n + " "); int count = 1; while (n!= 1){ if (n % 2 == 0){ n = n/2; else{ n = 3*n+1; System.out.print(n + " "); count++; System.out.println(); System.out.println("The number of numbers in the sequence is " + count);