JAVA Exam 1

@$U CSE 110

Which of the following refers to a collection of programs that a computer executes?

Software

Computers are machines that

execute programs

Computer programming is

the act of designing and implementing a computer program

Consider the following statements regarding computers:

I. Computers can execute a large number of instructions in a fraction of a second.

II. Computer application areas mainly target the research and scientific communities.

III. The physical components of a computer constitute its hardware.

IV. Unlike humans, a computer never gets bored or exhausted when performing repetitive tasks.

Which are true?

I, III, IV

Consider the following statements about computer programs:

I. Computer programs can be written by someone who has a basic knowledge of operating a computer.

II. Computer programs can complete complex tasks quickly.

III. Large and complex computer programs are generally written by a group of programmers.

IV. Computer programs are composed of extremely primitive operations.

Which are true?

II, III, IV

The Central Processing Unit is primarily responsible for

performing program control and data processing

A single silicon chip made from potentially millions of transistors is called

a Central Processing Unit (CPU)

An example of an output device that interfaces between computers and humans is

a speaker

An example of an input device that interfaces between computers and humans is

a microphone

Programs that are not running are usually stored

in secondary storage

When a program begins to run

it is moved to the CPU's memory

Which one of the following typically provides data persistence without electricity?

I. The CPU's memory

II. The hard disk

III. Secondary storage

II, III

Consider a scenario in which you develop a Java program on a computer that has a Pentium processor. What step should you take to run the same Java program on a computer that has a different processor?

The compiled Java machine language instructions can be run on any processor that has a Java Virtual Machine

High-level programming languages

are independent of the underlying hardware

Which one of the following translates high-level descriptions into machine code?

compiler

Computer scientists have devised something that allows programmers to describe tasks in words that are closer to the syntax of the problems being solved. This is called (an)

high-level programming language

Small applications written in the Java programming language that can be located on the Internet are called

applets

What is one of the benefits of using a high-level programming language like Java?

Problems solved in a high-level language are independent of the underlying computer

Because Java was designed for the Internet, which two of its attributes make it suitable for beginning programmers?

Safety and portability

An integrated development environment (IDE) bundles tools for programming into a unified application. What kinds of tools are usually included?

An editor and a compiler

Which of the following are reasons why Java is good, but not perfect, for beginners?

I. A certain amount of technical machinery is necessary to write basic, simple programs

II. There are many extensions

III. There are a large number of extensive libraries in Java

I, II, III

What is the difference between an editor and a compiler?

An editor allows program files to be written and stored; a compiler converts program files into an executable program

Suppose you examine a simple Java program and the first line is ' public Class HelloPrinter ' . Is this the same thing in Java as the line ' public Class helloprinter ' ?

No, because Java is case-sensitive, these are considered to be completely distinct

What statements about the integrated development environment (IDE) are true?

I. You may run Java class files even after exiting the IDE

II. The IDE can invoke a virtual machine, which is required to run a Java program

III. Translating Java source code into class files is enough to then actually run the program

I, II, III

Consider the following statements about folders and your integrated development environment (IDE):

I. Hierarchical folders help to organize a project

II. Folders are a way to visualize the layout of a file system

III. Folders make it impossible to lose or accidentally delete a file

I, II

Which of the following statements regarding backup strategies for Java files are true?

I. You should back up your projects often to prevent loss of valuable work

II. You should check your backups only in case of loss of data

III. You should pay attention to the backup direction

I, III

Every Java program consists of one or more

classes

Characters that are grouped together between double quotes (quotation marks) in Java are called

strings

Every statement in Java must be terminated with

the semi-colon character ;

These two lines of code do not produce the same output. Why?

System.out.println(7 + 3);
System.out.println("7 + 3");

The quotes cause the second expression to be treated as a string

What is the output from this code snippet?

System.out.print("The sum is ");
System.out.println("7 + 3");

The sum is 7 + 3

Which of the following symbols is used to terminate a Java program statement?

semicolon

Which of the following statements is valid with respect to the usage of a semicolon in Java?

A semicolon is used to denote the end of a statement

Which of the following statements is true with respect to the main method in Java?

Every Java application must have a main method

A Java class with the name Printer has to be saved using the source file name:

Printer.java

Which statement starts the declaration of a class in Java?

public class Classname

Which Java statement prints a blank line?

System.out.println();

Which Java statement does not contain an error?

System.out.println();

What is the output of the following code snippet?

System.out.print(4 + 4);
System.out.print(12);

812

What kind of error is it when your program has a syntax error?

Compile-time error

When a compiler finds a syntax error in a program, what happens?

The compiler continues and may report about other errors but does not produce a Java class file

What kind of error is created by the following code snippet?

System.outt.println("Hello");

Syntax error: the program will not compile

What kind of error is created by the following code snippet?

System.out.print("The sum of 8 and 12 is ");
System.out.println(8*12);

Logic error: the program does not produce the desired result

What is a logic error?

An error that occurs when a program is running because, for example, the wrong operator was used

How do programmers find exceptions and run-time errors?

Testing by running the program with a variety of input values

The programmer, not the compiler, is responsible for testing a program to identify

Run-time errors

Which one of the following errors represents a part of a program that is incorrect according to the rules of the programming language?

Syntax errors

Who or what is responsible for inspecting and testing the program to guard against logic errors?

Programmer

When developing a program, the programmer adds the discount amount to the total instead of subtracting it. What type of an error is this?

A logic error

Which one of the following methodologies is a sequence of steps formulated in English for solving a program?

Pseudocode

In order to run Java programs on a computer, the computer needs to have software called a(n)

virtual machine

In order to translate a Java program to a class file, the computer needs to have software called a(n)

compiler

The Java statement public static void main(String[] args) declares a

method

A Java virtual machine is

software

Which of the following statements must you include in a Java class that can be executed by the virtual machine?

public static void main(String[] args)

What is the output of the following code snippet?

System.out.print("Hello");
System.out.println("Good Day!");

HelloGood Day!

Which one of the following code snippets compiles without errors and displays the output "Hello Good Day!" on the screen?

System.out.print("Hello ");
System.out.println("Good Day!");

What is the output of the following code snippet?

public class PrintIt{
public static void main(String[] args){
System.out.println("4 * 4" + 12);
}
}

4 * 412

Writing a computer game in Java that has graphics, motion, and sound effects

requires a team of skilled programmers

Which option correctly completes this statement?

Programs can repeat simple instructions very quickly to

I. help human users to perceive images and sound

II. remove the drudgery of repeating instructions by hand

III. overcome the need for connectivity to the computer network

I, II

The ENIAC computer burned out transistors at the rate of

none \-- it used vacuum tubes

In order for the ENIAC computer to be re-programmed

wires needed to be plugged into a different wiring configuration

The language developed by Sun Microsystems that became the Java programming language was originally designed to be simple, secure, and

usable for many different processor types

The term "applet" refers to

a Java program that runs within a web browser

Programmers have embraced Java over its closest rival, C++, mainly because

it is easier to use

Java is said to be a "safe" programming language. What does this mean?

Java programs can run within a browser without fear that they may attack your computer

In order for Java to achieve protability

compiled Java programs contain instructions for a virtual machine

A Java Virtual Machine is

a program that simulates a real CPU

The Java programming language is itself relatively simple, but also contains a vast set of

library packages

The source code for a Java program is stored in a file

that ends with a.java suffix

A Java "class" file

contains instructions to the Java virtual machine

Which pointers about backing up your Java projects are important?

I. Check your backups once in a while

II. Rely on the Java programming language's built-in back up system

III. Back up often

I, III

Which statements are true?

I. In Java, a file can contain at most one public class

II. The word public denotes that the class is usable by the "public"

III. Every Java program must have a main method

I, II, III

The technical term for the values that a method needs in order to carry out its task is an argument. When there is more than one argument needed by a method, they are

separated by commas

In Java, if you want the compiler to interpret what you type as program instructions, you must

write correct Java statements separated by the semicolon

In Java, the statement

System.out.print("hello");;;

is a legal statement

Sometimes errors throw the compiler off track because

the compiler does not give up when it find the first error

Some run-time errors are so severe that they generate

an exception

During program development, errors are

unavoidable

If you misspell a word in your Java program it may be true that

I. the program will not compile

II. the program may compile, but not run

III. the program may compile and run but still have a logic error

I, II, III

Which of these are true about writing algorithms in pseudo code?

I. The exact wording is not important

II. The sequence of steps should be ambiguous

III. The algoirthm should terminate

I, III

A sequence of steps that is unambiguous, executable, and terminating is called

an algorithm

The first step in describing an algorithm in pseudo code is

determine the inputs and outputs

1) Which of the following loops executes the statements inside the loop before checking the condition?

a) for
b) while
c) do
d) do-for

Answer: c) do

2) How many times will the following loop run?

int i \= 0;
while (i < 10)
{
System.out.println(i);
i++;
}

a) 0
b) 8
c) 9
d) 10

Answer: d) 10

int i \= 0;
while (i !\= 9)
{
System.out.println("" + i);
i \= i + 2;
}

a) No output
b) 0 2 4 6 8
c) 10 12 14 16 18 .... (infinite loop)
d) 0 2 4 6 8 10 12 14 .... (infinite loop)

Answer: d) 0 2 4 6 8 10 12 14 .... (infinite loop)

4) How many times does the code snippet given below display "Loop Execution"?

int i \= 1;
while (i !\= 10)
{
System.out.println ("Loop Execution");
i++;
}

a) Infinite times
b) 8 times
c) 9 times
d) 10 times

Answer: c) 9 times

5) What is the output of the code fragment given below?

int i \= 0;
int j \= 0;
while (i < 27)
{
i \= i + 2;
j++;
}
System.out.println("j\=" + j);

a) j\=27
b) j\=12
c) j\=13
d) j\=14

Answer: d) j\=14

6) What is the output of the following code snippet?

int i \= 1;
while (i < 10)
{
System.out.print(i + " ");
i \= i + 2;
if (i \== 5)
{
i \= 9;
}
}

a) 1 3 5
b) 1 3 9
c) 1 3 5 7 9
d) 1 3 5 9

Answer: b) 1 3 9

7) The code snippet below checks whether a given number is a prime number. What will be the result of executing it?

public static void main(String[] args)
{
int j \= 2;
int result \= 0;
int number \= 0;
Scanner reader \= new Scanner(System.in);
System.out.println("Please enter a number: ");
number \= reader.nextInt();
while (j

Answer: b) The code snippet will display the desired result.

8) What are the values of i and j after the following code fragment runs?

int i \= 60;
int j \= 50;
int count \= 0;
while (count < 5)
{
i \= i + i;
i \= i + 1;
j \= j - 1;
j \= j - j;
count++;
}
System.out.println("i\=" + i + ", j\=" + j);

a) i \= 1951, j \= 0
b) i \= 1951, j \= 45
c) i \= 65, j \= 1
d) i \= 65, j \= 45

Answer: a) i \= 1951, j \= 0

9) Which error type does the "off-by-one" error belong to?

a) Syntax error
b) Compile-time error
c) Run-time error
d) Infinite loop

Answer: c) Run-time error

10) How many times does the following code fragment display "Hi"?

int i \= 10;
while (i \>\= 0)
{
System.out.println("Hi");
i--;
}

a) 9 times
b) 10 times
c) 11 times
d) 12 times

Answer: c) 11 times

11) What is the output of the following code fragment?

int i \= 1;
int sum \= 0;
while (i

Answer: b) The value of sum is 66

12) How many times does the loop execute in the following code fragment?

int i;
for (i \= 0; i < 50; i \= i + 4)
{
System.out.println(i);
}

a) 11
b) 12
c) 13
d) 14

Answer: c) 13

13) How many times does the following code snippet display "Loop Execution"?

for (int i \= 0; i < 10; i++);
{
System.out.println("Loop Execution");
}

a) Ten times.
b) The code snippet does not run because of a compile error.
c) Infinite loop.
d) Only one time.

Answer: d) Only one time.

14) What is the output of the code snippet given below?

int i;
int j \= 0;
for (i \= 0; i < 5; i++)
{
if (i % 2 \== 0)
{
i \= i + 2;
j++;
}
else
{
i++;
j \= j + 2;
}
j++;
}
System.out.println("i\=" + i + ", j\=" + j);

a) i\=7, j \=7
b) i \=7, j \=6
c) i \=6, j \=7
d) i \=5, j \=5

Answer: d) i \=5, j \=5

15) Which loop does not check a condition at the beginning of the loop?

I. The do loop
II. The while loop
III. The for loop

a) I and II
b) I and III
c) I only
d) III only

Answer: c) I only

16) How many times does the following loop run?

int i \= 0;
int j \= 1;
do
{
System.out.println("" + i + ";" + j);
i++;
if (i % 2 \== 0)
{
j--;
}
}
while (j \>\= 1);

a) 0 times
b) 1 times
c) 2 times
d) 4 times

Answer: c) 2 times

17) A loop inside another loop is called:

a) A sentinel loop
b) A nested loop
c) A parallel loop
d) A do/while loop

Answer: b) A nested loop