PLTW Computer Science FINAL EXAM

User Story

a written description of a program written from the perspective of a user

User-Centered

When you are developing an app, or any software solution, it is important to think about people who will be using that softare.

User Interface

the inputs and outputs that allow a user to interact with a piece of software. User interfaces can include a variety of forms such as buttons, menus, images, text, and graphics.

Calling a Procedure

To direct a program to execute or reference a certain procedure. A procedure is a subroutine that is stored only once but can be called many times in a program to execute when needed.

If-Then-Else Conditional Statements

1. Boolean expression of input: Yes/No - True/False
2. If True or Yes, then a value is inputted and the operation continues.
3. If False or No, then a value is not inputted and "else" is initialized.
4. If Else, the 1st input is not true or yes, then the second condition is met.

Global vs. Local Variables

Both variables are stored data. Global variables are accessible by any part of the program at any time. Local variables are only accessible by particular parts of the program.

While Loops

A control structure that allows a piece of code to repeated until a certain condition is false

The Software Development Process

1. Investigate
2. Plan
3. Design
4. Create & Test
5. Evaluate the Solution
6. Document and Present

Event-Driven Programming

some program statements run when triggered by an event, like a mouse click or a key press

Index/Indices

A specific location by order for an individual element in a list.

Abstraction

the result of creating a program where the focus is on what each step does instead of how the steps are performed. Also, the method or procedure used to control difficulty in a computer program or system.

Best-So-Far Loop

A piece of code (loop) that contains a variable which stores the "best" value as defined by the programmer. Each time the code executes the loop, the program evaluates whether it finds a "better" value as defined by the programmer. If it finds one that is better, then it replaces that variable value with the new value and continues until it reaches the end of the list.

Feature

A function of an application or user interface.

TEMP Chart

A model for building vocabulary: Term, Example, Meaning, Picture.

Component

A function or artifact in an app that you can add in design view of MIT App Inventor. E.g., Canvases, Cameras, Labels, Sliders, Sounds, Horizontal Arrangements, & Buttons

Event

An action or occurrence that happens during runtime that will trigger a response or behavior by the software.

Event Handlers

A control block that looks for inputs or events to know when to perform a specific action.

Procedures

A sequence of actions or instructions to follow in solving a problem or accomplishing a task. Also called subprogram.

Debugging

To identify errors or bugs in computer hardware or programs and fix them.

Input

Information or signals entered into a computer system using an interface

such as buttons, keys on a keyboard, touch screens, & accelerometers.

Output

Information or signals produced or delivered by a computer system.

Iteration

A process of repeating a set of instructions a specified number of times or until a condition is met.

Variables

The smallest unit of data storage that a program can use.

This includes known or unknown information referred to as a "value".

Variables are either global or local.

Arguments

The values that a program provides to a function or subroutine.

These are also referred to as parameters.

Strings

Text or characters displayed by a program.

Concatenation

A joining together of separate items

\- without changing them

\- into one place.

Arithmetic Operators

A symbol in code that tells a computer to perform a specific math operation,

such as addition, subtraction, multiplication, or division.

Relational Operators

The = ≠ > < operators used to compare two items.

They are also referred to as comparison operators.

Logical Operators

A representation of a logical statement that is used to examine the

relationship between two values and determine whether the statement is true

or false. Examples of logical operators are AND, OR, and NOT.

Conditional Statements

A programming statement that evaluates a true/false Boolean expression to

determine the next steps in a program. Conditional statements are often

written as "if-then" or "if-then-else" statements.

Boolean Expressions

A processing decision branch using relational operators (= ≠ >

Boolean Operators

● not

● equal to

● and

● or

Transistor

A physical component that can make yes/no & true/false decisions.

Chained Conditional Statements

A series of conditional statements which a computer executes

until it finds one that is true.

Integer

A whole number that does not have a decimal or any digits after the decimal.

Procedure

A sequence of actions or instructions to follow in solving a problem or

accomplishing a task. A procedure is a group of statements that may be used

at one or more points in a computer program.

These are also referred to as subprograms.

Backlog

A sequential and prioritized list of what needs to be done to create the app

the user wants. The list can be technical requirements or user centric in the

form of user stories.

Sprint-Task-List

A list of individual parts that need development to address a backlog item.

Scope

A description of the parts of a program where a particular variable can be

accessed and modified.

Natural Language

The language that people use in daily conversations with each other.

Pseudocode

A way to work out the logic without worrying too much about the specifics

of the language you are programming in.

Incremental Counter

A loop that changes the value of a count by a certain amount every time an event occurs.

Decrement

To reduce in number by one.

Loop

A sequence of instructions that continually repeats until a condition is met.

A loop is a type of iteration.

Problem Decomposition

The process of breaking a complex problem or system into parts that are

easier to conceive, understand, program, and maintain.

Sprints

The individual parts that need development to address a backlog item.

Local Database

A storage space on a device used to store information from an app.

Procedural Abstraction

The process of applying or using a procedure and only knowing what the

procedure does, without knowing how it does it.

Function

A named section of a program that performs a specific task. A function is a

block of organized and reusable code that performs a single action. A

function can be a procedure or a subroutine.

Method

A function that is a member of a class.

Class

A template for creating objects. A class is a grouping of functions and

associated data into a cohesive unit that specifies the methods and attributes

(also called properties) that are related to an object.

When an object is created from a class, the resulting object is called "an

instance of the class."

Modulo

A mathematical operator that performs division but returns the remainder.

Accumulator

A role that a variable may take on in which it keeps a running or cumulative

total or value.

Commonly an accumulator is initialized outside of a loop, assigned new

values within the loop, and then its result is used outside of the loop.