Prog IV Chapter 2 Review

Program Basics

100

What file extension must all Java source code files end with?

.java

200

Every Java application program must have what method?

A method named main

300

Identify the class name in this program:

public class Funk {
    int fly;
    public static void main(String[] args) {
        System.out.println("Hello, world!");
    }
}

Funk

400

What symbol is used to mark the beginning and end of a code block in Java?

{}

500

How is a Java source file named? (what comes before the .java?)

It is named after the public class with .java

Output and Escape Sequences

100

How is print different from println?

print does not move to a new line and println does

200

What escape sequence moves output to a new line?

\n

300

What does '\t' do?

Prints a tab

400

What will this code display?

System.out.print("ABC\bD");

ABD

500

What does this code print?

System.out.print("She said "Hi"");

It won't compile because quotes are printed with \"

Variables & Naming

100

What is a variable?

A named storage location in memory

200

Is Sales the same variable name as sales?

No - Java is case-sensitive

300

What does this program not display the value of the variable?

number = 10

System.out.println("number is" + "number");

number isnumber

400

Identify the variables and literals in this program:

int apples = 10;
double price = 1.5;
System.out.println("Total cost: " + apples * price);

Variables: apples, price

Literals: 10, 1.5, "Total cost: "

500

Which of the following is not a legal variable name: 

$x

99bottles

_java_rocks_

FoxInSocks

99bottles

Data Types & Constants

100

Identify the data type:

true

boolean

200

What is the difference between a variable and a named constant?

A variable can change; a named constant cannot

300

What keyword is used to declare a constant in Java?

final

400

What is the difference between a float and a double?

A double stores more precision and uses more memory than a float

500

What is the value of answer?

double answer = 17/10;

1

Strings, Scope & Comments

100

What method returns the number of characters in a String?

length()

200

How do you write a single-line comment in Java?

// comment

300

How do you write a multi-line comment in Java?

/* comments

more comments 

comment */

400

What object is used to read user input from the keyboard?

Scanner

500

What does this program do?

public class TestScope {
    public static void main(String[] args) {
        System.out.println(x);
        int x = 5;
    }
}

Nothing, it won't compile.  x is used before it's declared.