Computer Science Terms

static

Belongs to the class, not an object. You can use it without making an object. Example idea: Math methods are static, like Math.sqrt(9).

void

Method that does something but doesn’t return a value. Example idea: print a message or update something.

constructors

Special setup methods that run when you make an object. Example idea: sets the name or starting values.

class

The blueprint for making objects. Example idea: like a recipe that tells what an object can do and what it has.

return

Tells the method to send a value back. Example idea: return the answer to a math problem.

Escape sequences

Special symbols inside quotes that mean new line, tab, or quote. Example idea: \n makes a new line, \t adds space.

indexOf

Finds where a letter or word starts in a string. Example idea: in "hello", l starts at 2.

substring

Makes a smaller part of a string. Example idea: "computer" can become "pute".

substring(int start)

Takes the part of a string starting from that spot to the end. Example idea: from 3 gives everything after index 3.

substring(int start, int end)

Takes part of a string from start up to but not including the end number. Example idea: (1,4) gets letters 1 to 3.

compareTo(String s)

Compares two words alphabetically. Returns 0 if same, negative if before, positive if after. Example idea: apple comes before banana.

equals(String s)

Checks if two strings are exactly the same. Example idea: "dog" and "Dog" are not equal because of capital letters.

void methods

Do an action but don’t return anything. Example idea: print, change, or display something.

return methods (with and without parameters)

Give back a value. Some need info (parameters), some don’t. Example idea: return 5 or add two numbers.

return methods on an object

Return something about that object. Example idea: getName returns the person’s name.

Attribute

A piece of data that describes an object. Attributes store information about an object.

Instance Variable

A variable defined in a class that belongs to each object created from that class. Each object has its own copy.

Method

A block of code that performs an action or task. Methods define what an object can do.

Behavior

What an object can do. Behavior is implemented using methods.

Class

A blueprint or template used to create objects. It defines attributes and methods.

Class

A real thing created from a class. An object represents a specific instance of a class.

Instance

One specific object created from a class. “Object” and “instance” mean the same thing in most cases.