AP Computer Science A Prep, 2024 - Rob Franek 2023
Glossary
Symbols
== (is equal to): a boolean operator placed between two variables that returns true if the two values have the same value and false otherwise [Chapter 5]
!= (is not equal to): a boolean operator placed between two variables that returns false if the two variables have the same value and true otherwise [Chapter 5]
&& (logical and): an operator placed between two boolean statements that returns true if both statements are true and false otherwise [Chapter 5]
! (logical not): a boolean operator placed before a boolean statement that returns the negation of the statement’s value [Chapter 5]
|| (logical or): an operator placed between two boolean statements that returns false if both statements are false and true otherwise [Chapter 5]
A
accessor methods: methods used to obtain a value from a data field [Chapter 7]
aggregate class: a class made up of, among other data, instances of other classes [Chapter 7]
array: an ordered list of elements of the same data type [Chapter 8]
ArrayIndexOutOfBoundsException: a run-time error caused by all calling of an index array that is either negative or greater than the highest index of the array [Chapter 8]
ArrayList object: an object of a type that is a subclass of List used on the AP Computer Science A Exam [Chapter 9]
assign: create an identifier by matching a data value to it [Chapter 3]
assignment operator: a single equals sign (“=”) indicating that an identifier should be assigned a particular value [Chapter 3]
B
base case: the indication that a recursive method should stop executing and return to each prior recursive call [Chapter 12]
binary: a system of 1s and 0s [Chapter 3]
binary search: a search of a sorted array that uses searches beginning in the middle and determines in which direction to sort [Chapter 8]
blocking: a series of statements grouped by {} that indicate a group of statements to be executed when a given condition is satisfied [Chapter 5]
boolean: a primitive data type that can have the value true or false [Chapter 3]
boolean operator ==: an operator that returns true if it is between two variables with the same value and false otherwise [Chapter 5]
C
casting: forcing a data type to be recognized by the compiler as another data type [Chapter 3]
character: a primitive data type representing any single text symbol, such as a letter, digit, space, or hyphen [Chapter 3]
class: a group of statements, including control structures, assembled into a single unit [Chapters 4, 7]
columns: portions of 2D-arrays that are depicted vertically. These are the elements of each array with the same index. [Chapter 10]
commenting: including portions of the program that do not affect execution but are rather used to make notes for the programmer or for the user [Chapter 3]
compile-time error: a basic programming error identified by the interpreter during compiling [Chapter 3]
compiling: translating a programming language into binary code [Chapter 3]
compound condition: a complicated condition that includes at least one boolean operator [Chapter 5]
Computer Science: different aspects of computing, usually development [Chapter 3]
concatenation operator: a plus sign (“+”) used between two strings indicating that the two string values be outputted next to each other [Chapter 3]
condition: the portion of a conditional statement that has a boolean result and determines whether the statement happens [Chapter 5]
conditional statement: a statement that is executed only if some other condition is met [Chapter 5]
constructor: a method in an object class used to build the object [Chapter 7]
D
decrement operator (--): a symbol used after a variable to decrease its value by 1 [Chapter 3]
double: a primitive data type representing numbers that can include decimals [Chapter 3]
driver class: a class that is created to control a larger program [Chapter 7]
dynamically sized: having the ability to change length and to insert and remove elements [Chapter 9]
E
enhanced-for loop: a for loop with a simplified call used to traverse an array [Chapter 8]
escape sequence: a small piece of coding beginning with a backslash to indicate special characters [Chapter 3]
F
fields: see instance variables
flow control: indication of which lines of programming should be executed in which conditions [Chapter 5]
for loop: a loop with not only a condition but also an initializer and incrementer to control the truth value of the condition [Chapter 6]
full: all values of the array are assigned [Chapter 8]
H
header: the “title” of a method used to indicate its overall function [Chapter 7]
I
identifiers: names given to indicate data stored in memory [Chapter 3]
if: a reserved word in Java indicating the condition by which a statement will be executed [Chapter 5]
immutable: having no mutator methods [Chapter 4]
increment operator (++): a symbol used after a variable to increase its value by 1 [Chapter 3]
index numbers: integers, beginning with 0, used to indicate the order of the elements of an array [Chapter 8]
infinite loop: a programming error in which a loop never terminates because the condition is never false [Chapter 6]
inheritance: the quintessential way to create relationships between classes [Chapter 11]
inheritance hierarchy: the quantification of relationships between classes by using “parent” and “child” classes [Chapter 11]
initializer list: known values used to assign the initial values of all the elements of an array [Chapter 8]
in-line comments (short comments): comments preceded by two forward slashes (“//”) indicating that the rest of the line of text will not be executed [Chapter 3]
insertion sort: a sorting algorithm in which smaller elements are inserted before larger elements [Chapter 8]
instance variables (fields): variables, listed immediately after the class heading, of an object that are accessible by all of the object’s methods [Chapter 7]
integer: a primitive data type representing positive numbers, negative numbers, and 0 with no fractions or decimals [Chapter 3]
interpreter: the part of the developer environment that enables the computer to understand the Java code [Chapter 3]
L
list object: an object form of an array with a dynamic size that can store multiple types of data
logical error: an error that lies in the desired output/purpose of the program rather than in the syntax of the code itself [Chapter 3]
long comments: comments that use (“/*”) to indicate the beginning of the comment and (“*/”) to indicate the end [Chapter 3]
loop: a portion of code that is to be executed repeatedly [Chapter 6]
M
merge sort: a sorting algorithm in which an array is divided and each half of the array is sorted and later merged into one array [Chapter 8]
method: a group of code that performs a specific task [Chapter 7]
method abstraction: a declaration in a superclass that all subclasses must either override the superclass method or declare the subclass method as abstract [Chapter 11]
multiple inheritance: an illegal activity in Java in which a subclass inherits from more than one superclass [Chapter 11]
mutator methods: methods used to change the value of a data field [Chapter 7]
N
null: the default value of an object that has not yet been assigned a value [Chapter 8]
NullPointerException: a run-time error caused by calling an object with a null value [Chapter 8]
O
object: an entity or data type created in Java; an instance of a class [Chapter 4]
object class: a class that houses the “guts” of the methods that the driver class calls [Chapter 7]
object reference variable: a variable name [Chapter 7]
overloading: using two methods with the same name but with different numbers and/or types of parameters [Chapter 7]
override: use a method in a subclass that possesses the same name, parameter(s), and return type as a method in the superclass, causing the subclass method to be executed [Chapter 11]
P
parameters: what types of variables, if any, will be inputted to a method [Chapter 7]
planning: outlining the steps of a proposed program [Chapter 7]
polymorphism: the ability of a subclass object to also take the form as an object of its superclass [Chapter 11]
postcondition: a comment that is intended to guarantee the user calling the method of a result that occurs as the result of calling the method [Chapter 7]
precedence: the order in which Java will execute mathematical operations, starting with parentheses, followed by multiplication and division from left to right, followed by addition and subtraction from left to right [Chapter 3]
precondition: a comment that is intended to inform the user more about the condition of the method and guarantees it to be true [Chapter 7]
primitive data: the four most basic types of data in Java (int, double, boolean, and char) [Chapter 3]
programming style: a particular approach to using a programming language [Chapter 3]
R
recursion: a flow control structure in which a method calls itself [Chapters 8, 12]
recursive call: the command in which a method calls itself [Chapter 12]
reference: a link created to an object when it is passed to another class and, as a result, received through a parameter [Chapter 7]
return type: what type of data, if any, will be outputted by a method after its commands are executed [Chapter 7]
rows: the portions of 2D-arrays that are depicted horizontally and can be seen as their own arrays [Chapter 10]
run-time error: an error that occurs in the execution of the program [Chapter 3]
S
search algorithms: methods of finding a particular element in an array [Chapter 8]
selection sort: a sorting algorithm in which the lowest remaining element is swapped with the element at the lowest unsorted index [Chapter 8]
sequential search: a search of all the elements of an array in order until the desired element is found [Chapter 8]
short-circuit: a process by which the second condition of an and or or statement can be skipped when the first statement is enough to determine the truth value of the whole statement [Chapters 5, 6]
short comments: see in-line comments
sorting algorithms: methods of ordering the elements within an array [Chapter 8]
source code: a .java file that defines a program’s actions and functions [Chapter 7]
span: a somewhat dated word that means using a loop to use or change all elements of an array. Now referred to as traverse.
static: when a program is running and there is only one instance of something. A static object is unique: a static variable is allocated to the memory only once (when the class loads). [Chapter 7]
static method: a non-constructor method that is designed to access and/or modify a static variable [Chapter 7]
static variable: an attribute that is shared among all instances of a class [Chapter 7]
string: see string literal
string literal (string): one or more characters combined in a single unit [Chapter 3]
strongly typed: characteristic of a language in which a variable will always keep its type until it is reassigned [Chapter 3]
subclass: a “child” class, with more specific forms of the superclass [Chapter 11]
superclass: a “parent” class, the most general form of a class hierarchy [Chapter 11]
super keyword: a keyword used to call an overridden method [Chapter 11]
T
traverse: use a loop to use or change all elements of an array [Chapter 8]
trace table: a table used to trace possibilities in conditionals [Chapter 5]
truth value: the indication of whether a statement is true or false [Chapter 5]
two-dimensional array (2D array): an array in two dimensions, with index numbers assigned independently to each row and column location [Chapter 10]
typed ArrayList: an ArrayList that allows only one type of data to be stored [Chapter 9]
V
variable: an identifier associated with a particular value [Chapter 3]
W
while loop: a loop that cycles again and again while a condition is true [Chapter 6]
white space: empty space intended to enhance readability [Chapter 3]