chapter 1 review

The instruction: System.out.println("Hello World"); might best be commented as:

// used to demonstrate an output message

Examine figure 1.7 before answering this question. What 8-bit value comes before and what 8-bit value comes after 10010111?

10010110 comes before and 10011000 comes after 10010111.

Which memory capacity is the largest?

12,000,000 megabytes

A color image is broken down into individual pixels (points), each of which is represented by a) a 1 for white and a 0 for black

3 values denoting the shade of red, green and blue in the image

Consider that the Pentium IV processor runs at a clock speed of about 850 MHz. What clock speed might we expect from a Pentium chip that would be released 3 years after the Pentium IV?

3400 MHz or 3.4 GHz.

6 bits can be used to represent ___ distinct items or values

64

A URL (Universal Resource Locator) specifies the address of

A document or other type of file on the Internet

What is a logical error? Give an example.

A logical error occurs when a program compiles and runs without complaint, but it produces incorrect output. An example is multiplying two numbers when they should have been added.

Which of the following stores data in binary format?

All information in a computer is stored in binary, that is, using 0s and 1s.

Java byte codes are directly executable whereas Java source code is not.

False

Mistyping "println" as "printn" will result in a run-time error.

False

A Java compiler can determine if you have followed both proper syntax and semantics.

False.

For a computer to communicate over the Internet it must use the Ethernet protocol.

False.

In a Java program, dividing by 0 is a syntax error.

False.

Java is a case-sensitive language meaning that Current, current, and CURRENT will all reference the same identifier.

False.

Java is an example of a fourth generation language.

False.

Modern computers store information in analog.

False.

RAM is random access memory while ROM is not random access memory.

False.

Reserved words in Java can be redefined by the programmer to mean something other than their original intentions.

False.

System.out.print is used in a program to denote that a comment follows.

False.

The CPU is made up of three important components: the control unit, registers, and main memory.

False.

The Java compiler is able to find all programmer errors.

False.

The line of Java code "// System.out.println("Hello");" will cause "Hello" to be output.

False.

The word "Public" is a reserved word.

False.

Of the following list, which one is not true regarding Java as a programming language?

It is a language whose programs do not require translating into machine language before they are executed c) It is an object-oriented programming language

What is wrong with the following println statement? System.out.println("My fourth Java Program);

It is missing a close ". The compiler will look for a second " before the end of the statement. So, like { }, ( ), and [ ], " must have a close ".

Which character below is not allowed in an identifier?

Java identifiers can consist of any letter, digit, $ or _ as long as the identifier starts with a letter or _. ^ is not a legal character.

Which of the following would be a legal Java identifier?

Java identifiers cannot have the characters "!", "'" or "-" in them making answer c, d and e wrong. The word "class" is a reserved word in Java and cannot be used as an identifier. The identifier "i" is perfectly legal although not necessarily a good identifier since it is not descriptive of its use.

Which of the following is a legal Java identifier?

Java identifiers cannot start with a number (so the answers in a, d and e are illegal) and cannot include the "/" character, so one/4/all is illegal.

Provide a brief explanation of the role of main memory, the control unit, the arithmetic logic unit, and registers.

Main memory is used to store the currently executing processes along with their data. The control unit performs the fetch-decodeexecute cycle, which fetches an instruction from memory, decodes it and determines how it is to be executed. The arithmetic logic unit comprises a number of circuits that execute arithmetic and logic instructions. Registers are used to store values in the CPU temporarily while the current instruction(s) need them.

In order for a computer to be accessible over a computer network, the computer needs its own

Network address

Volatility is a property of

RAM

Following Java naming convention, which of the following would be the best name for a class about store customers?

StoreCustomer

Which of the following would not be syntactically legal in Java?

The Java compiler would not recognize "s t a t i c" as "static" because the Java compiler treats white space (blanks) as separators between entities. The other statements are all legal, including "{ }" which is a block that happens to have no statements inside of it.

What is wrong with the following class definition? public class Program2 public static void main(String[] args) { System.out.println("My second Java program"); }

The definition of a class is placed within { } statements, which are missing here.

What is wrong with the following class definition? public class Program1 { public static void main(String[] args) { System.out.println("My first Java program") } }

The one executable statement in the main method is missing a ";" at the end of the line. Executable statements end with ";".

Given the following class definition, what are the reserved words and what are the identifiers? public class Program3 { public static void main(String[] args) { System.out.println("My third Java program"); } }

The reserved words are public, class, static, void, main. The identifiers are String, System.out, Program3 and args. String and System.out are classes already defined in Java and println is a method of System.out. Program3 is a class, defined here, and args is a variable.

All information is stored in the computer using binary numbers.

True

Java is an object-oriented programming language.

True

The "execute" phase of the fetch-decode-execute cycle might use a circuit in the arithmetic-logic unit.

True

A black and white picture can be stored by representing each pixel using a single bit.

True.

A unique aspect of Java that allows code compiled on one machine to be executed on a machine of a different hardware platform is Java's bytecodes.

True.

An operating system is considered software.

True.

Binary numbers are composed entirely of 0s and 1s.

True.

Code placed inside of comments will not be compiled and therefore will not execute.

True.

Data written to a memory location overwrites and destroys any information that was stored at that location.

True.

One terabyte is equivalent to approximately 1000 gigabytes.

True.

Rewrite the following comment so that it can appear over multiple lines. // This is one really enormously long comment that might run off the page

We can do this in two ways, preceding each line with // or by enclosing the comment in /* and */ /* This is one really enormously long comment that might run off the page */ // This is one really enormously // long comment that might run // off the page

An error in a program that results in the program outputting $100 instead of the correct answer, $250 is

a logical error

Forgetting a semicolon will cause

a syntax error

Provide a brief description of the roles of the following hardware elements (that is, what each is used for): a) CPU b) Main memory c) Secondary memory devices d) Input/Output devices

a) The CPU is the processor, it executes all program instructions. It does this through the fetch-decode-execute cycle where the next program instruction is fetched from memory, decoded in the CPU and executed by one or more circuits. b) Main memory is stored on chips on the motherboard and is used for quick access to the current program for the fetch-decode-execute cycle and to store data being used by this program. c) Secondary memory devices are storage devices, used to store programs and data not currently being used. Storage devices, such as the hard disk, are also used to store things for permanence and archives. d) Input/Output devices are used to communicate with the computer. Input devices, like the keyboard, take commands and data from the user and output devices, like the monitor, display the results of the process/computation.

Once we have implemented the solution, we are not done with the problem because

a) the solution may not be the best (most efficient) b) the solution may have errors and need testing and fixing before we are done c) the solution may, at a later date, need revising to handle new specifications d) the solution may, at a later date, need revising because of new programming language features

Comments should

be insightful and explain what the instruction's intention is

Which of the following would be a good variable name for the current value of a stock?

currentStockVal

What is the output of the following when the main method is executed? public class Question { public static void main(String[ ] args) { System.out.println("hi there"); System.out.println(" "); System.out.println("how are you doing today? "); } }

hi there how are you doing today? Notice that while the Java compiler ignores "white space", blanks that appear in a println statement inside of quote marks are retained and output in that manner.

When executing a program, the processor reads each program instruction from

main memory

It is important to dissect a problem into manageable pieces before trying to solve the problem because

most problems are too complex to be solved as a single, large activity

Rewrite the following program with better formatting to make it easier to read. public class MyProgram { public static void main( String[ ] args) { System.out.println( "Wow, this is messed up!" ); } }

public class MyProgram { public static void main(String[ ] args) { System.out.println("Wow, this is messed up!"); } }

Write a Java program that outputs "Java!" when run.

public class OutputJava { public static void main (String[] args) { System.out.println("Java!"); } }

The main method for a Java program is defined by

public static void main(String[ ] args)

The ability to directly obtain a stored item by referencing its address is known as

random access

Provide identifier names that would be used to represent a person's social security number, income tax withheld, and net pay.

socialSecurityNumber, or ssn, incomeTaxWithheld or incomeTax, and netPay would all be reasonable.

A Java program is best classified as

software

Which of the following characters does not need to have an associated "closing" character in a Java program?

{ is used to open a block, and so } is needed to close the block. ( is used to open an expression and so ) is needed to close an expression. [ is used to start an array index so ] is needed to close the array index. < is "less than" and > is "greater than" and these are not needed together, so < requires no closing character.