Computer Science A Unit 3

Hold only one piece of data at a time

Boolean, int, double

stored as an actual value

hold more than one piece of data type

Int, double, String, Scanner

have built-in tools - tools which you can use to work with an manipulate data

memory address that points to the place where info is stored (don’t site the actual value)

means you cannot change Strings without moving to a new memory location. Java will do this automatically.

Placeholder that means no reference

Rules that tell us the sequence in which the code is run

Each character of a String is stored individually

Each character is given an address that starts at 0

The address number of each character

Tells us the length of the String

Tests if 2 strings are equal - If the same contents of both Strings heave the same characters in the same places

Will return the true or false (Boolean)

Creates a subset of characters from the starting index up to but not including the stopping index

Returns the subset of characters from the start to the end of the String

Returns the String changed to the uppercase letters

Returns the string changed to the lowercase letters

Lets us compare 2 Strings alphabetically

Method that allows you to search through a String to find a particular character

Returns the index position as an int

Specific instance of a class with defined attributes

Define true attributed for objects

Store and represent data associated with objects whose behaviors are defined by the methods

Specific object that is created from the class

The process of creating a new object

Special method that creates a new object

Every class defines its own constructor

Doesn’t have a return type in Java

Information we put in () and determines how we construct our new object

Application Programming Interface

It’s the way programmers share information or code with each other

Attributes of the object and their values (at a given time) that define what our object (ex: rectangle) looks like

Characteristics of a circle: round, radius, diameter, circumference, pi

True for the Circe class

Performs an action, but doesn’t return any information

Generally changes the state of an object

Changes the state of an object and returns a value to us

Mostly used for pulling information for an object

By quantity (number of parameters)

By data type

By different order

Made up of methods name, number of parameters, and the data type of those parameters

Java determines which method to call based on parameter number and number and data types - the method signature

Signatures can only have the same name - those are overloaded methods - but they have to be different parameters

Wraps a primitive data type into objects/class so we can apply methods to them

Compare 1 integer to another integer

Compares 1 double to another double

Automatic conversion between primitive data types and their corresponding object wrapper classes

When java is given an Integer and expects an int, it automatically converts, or unboxes, the integer into a primitive int.

Part of Java.lang package

We need to make sure it is imported to our program

Performs an absolute value calculation

int the as an input→ int as an output

double used → double returned

Performs exponent math

Accepts 2 parameters: the base and the exponent

Performs a calculation: base (x) raised to the exponent power (y)

Calculates the square root of the double we send it

Returns a double

Returns a double from 0.0 to but not including 1.0

Specify the object, then the method to perform on the object

Performed just by referencing the Class name