Midterm Flashcards
Which of these is not a primitive data type in Java?
a. int
b. String
c. float
d. Boolean
b. String
In System.out.println(“hello world”); System is a ________, println is a _________ and “hello world” is a _________
a. method, class, return-type
b. class, parameter, method
c. variable, method, parameter
d. class, method, parameter
d. Class, method, parameter
The formula for the volume of a sphere is
V= 4/3πr^3
In Java, the radius is saved as a double variable r. To calculate volume in Java we write
a. double v = 4Math.PIMath.pow(r, 3)/3;
b. double v = 4Math.PI()rrr/3;
c. double v = (4/3)Math.PIMath.pow(r, 3);
d. double v = (Math.PI()Math.pow(r, 3)4)/3;
a. double v = 4Math.PIMath.pow(r, 3)/3;
Scanner x = new Scanner(System.in); How would be input an integer and save it in variable count.
a. int count = input.nextInt;
b. int count = input.nextInt();
c. int count = x.nextInt;
d. int count = x.nextInt();
d. int count = x.nextInt();
The command to compile a file HelloWorld.java is
javac HelloWorld
To use the debugger in Eclipse, we create _____________ in the program where execution will pause and allow us to inspect variables.
Breakpoints
double x = 3.4567;
Which of these will print 3.46
a. System.out.print(x);
b. System.out.printf(“%.2f”, x);
c. System.out.printf(“%.3f”, x);
d. System.out.printf(“%f”, x);
b . System.out.printf(“%.2f”, x);
Git is a
Version Control System
double x = 31;
int y = 10;
Which of these will print Happy Halloween 10/31
a. System.out.printf(“Happy Halloween %d/%f”, y, x);
b. System.out.printf(“Happy Halloween %f/%d”, y, x);
c. System.out.printf(“Happy Halloween %d/%.0f”, y, x);
d. System.out.printf(“Happy Halloween %.0d/%f”, y, x);
c. System.out.printf(“Happy Halloween %d/%.0f”, y, x);
What is the Git command git innit used for?
Initializes a local git repository
What is the Git command git commit used for?
Takes everything thats in the index/staging area and commits it to the local repository
Who created Git?
Linus Torvalds and the Linux community
What is version control?
The tracking and managing of changes to software code
What does the Git command git add <file> used for?</file>
Adds the selected files to the staging area of the index, ready not to be commit
What is the Git command git status used for?
Checks what you have in the index/staging area, shows the differences between the working tree and the staging area
What is the Git command git push used for?
Pushes the local repository you have created and pushes it to a remote repository
What is the Git command git pull used for?
Pull the latest version from a remote repository
What is the Git command git clone used for?
Clones the repository into a new directory
The java compiler translates a .java file to generate a _____ file (what file extension for the created file?)
.class file
What command line command, reports the version of the Java compiler installed?
javac -version
What command line command, reports the version of the Java Runtime Environment installed?
java -version
When working in Eclipse, to edit and compile code you use the _____.
Editor or Workbench
What is the default file extension for UMLet diagrams?
.UXF
What does this line of code do?
int value1 = Integer.parseInt(“42”);
42 is a string, parseInt(String) converts it into an int
T/F - A string variable can hold digits such as account numbers and zip codes
True
Declaring a class does create actual objects
True
The data components of a class that belong to every instantiated object are the class’s _____ variables
Instance
The access specifier in the declaration of instance variables should be _______
private
A method header consists of which of the following parts?
An access specifier, a return type, a method name, and a list of parameters
By using _________ you can use reasonable, easy-to-remember names for methods and concentrate on their purpose rather than on memorizing different method names
method overloading
What does static do in a class?
Which operator computes the remainder of an integer division?
%
a ________ evaluation is where each part of an expression is evaluated only as far as necessary to determine whether the entire expression is true or false
Short circuit
Area of a circle
πr^2
circumference of a circle
2πr
Volume of a rectangular prism
LWD
Volume of a cone
πr^2h/3 or (1/3)πr^2h
The command to compile a file HelloWorld.java is
javac HelloWorld.java
In flowcharts, input and output is always shown in ________
Parallelograms
Breaking large sequences of processing steps into smaller, reusable units in a computer program
Functional decomposition
Methods are also known as
Modules
Arguments are the actual inputted variable form of
parameters
Variables declared inside of a method body are part of that methods _____ and are not visible in other method bodies
local scope
a _____ is a blueprint for an ________
Class, Object
What is an object?
an object is an allocation of memory that contains properties and behaviours
Each object is also called is also called an _____ of the class
instance
A property is usually a
adjective
An object is typically a
noun
A (behaviour) method is typically a
verb
A UML Class Diagram looks like a rectangle or column with __ rows
3
A UML Class Diagram record the _____ and _____ for a class
Properties and behaviours
Instance variables are declared at the _____ level
Class
a java object property/attribute is implemented using 3 things:
Instance variable, accessor and mutator
2 Ways to identify a constructor
- Same name as class
- No return type
Primitive types: name the groups
4 Numeric no INT
Byte Short Int Long
2 numeric with INT
Float Double
1 Logic
Bool
1 Numeric storing letters
Char
Bits of memory
Byte
Short
Int
Long
8, 16, 32, 64
Should you use float or double for money calculations?
Neither
You cannot assign a ____ to a ____ or vice versa
Char, String
What does keyword static cause to happen when applied to a class-level variable?
The variables becomes part of the class and is shared by any instance
Why do we use static and final for class-level constants?
The value never changes, so to save memory we only keep one copy of value in memory (static)
A reference type variable contains a ______ not a ______
reference-value, object
x=5
y=10
x++ =?
++y=
x++ + ++y =?
6, 10, 16 since x++ takes place after the equation
outputs
Print (“test” + 1 + 2)
Print(1 + 2 + “test”)
test12
3test
