APCSP

Algorithm

a finite set of instructions that accomplish a specific task.

Code statement

a part of program code that expresses an action to be carried out.

Expression

can consist of a value, a variable, an operator, or a procedure call that returns a value; expressions are evaluated to produce a single value.

Execute

the process of running a computer software program, script, or command.

Behavior

how a program functions during execution; often described by how a user interacts with it.

Program inputs

data sent to a computer for processing by a program; it can come in a variety of forms, such as tactile, audio, visual, or text.

Program outputs

any data sent from a program to a device; can come in a variety of forms, such as tactile, audio, visual, or text.

 

Event

an occurrence; things that happen; usually associated with an action (i.e. mouse click, button pressed).

Event handler 

a part of code that 'handles' or listens for a specific type of event; when that event occurs, the code inside the event

Program documentation

a written description of the function of a code segment, event, procedure, or program and how it was developed.

Comments

a form of program documentation written into the program that helps explain what the code is doing. Comments in a program do not affect how a program runs.

Logic error

a mistake in the algorithm or program that causes it to behave incorrectly or unexpectedly.

Syntax error

a mistake in the program where the rules of the programming language are not followed.

Run-time error

a mistake in the program that occurs during the execution of a program; programming languages define their own run-time errors.

Overflow error

an error that occurs when a computer attempts to handle a number that is outside of the defined range of values.

Testing

using defined inputs to ensure that an algorithm or program is producing the expected outcomes, in the development process.

Sequencing

the application of each step of an algorithm in the order in which the code statements are given.

Selection

determines which part of an algorithm are executed based on a condition being true or false.

Nested conditional statements

consist of conditional statements within conditional statements.

Iteration 

a repeating portion of an algorithm; iteration repeats a specified number of times or until a given condition is met.

Variable

an abstraction inside a program that can hold a value. Each variable has associated data storage that represents one value at a time, but that value can be an array/list or other collection that in turn contains multiple values.

Variable Types

some programming languages provide types to represent data. These types include numbers, Booleans, arrays/lists, and strings.

Element

an individual value in an array/list that is assigned a unique index.

Index

a common method for referencing the elements in a list or string using natural numbers.

String

an ordered sequence of characters.

String concatenation

joins together two or more strings end-to-end to make a new string.

Substring

part of an existing string.

Boolean value

a variable that is either true or false.

Data abstraction

provides a separation between the abstract properties of a data type and the concrete details of its representation; manages complexity in programs by giving a collection of data a name without referencing the specific details of the representation.

Procedural abstraction

provides a name for a process and allows a procedure to be used only knowing what it does, not how it does it; allows a solution to a large problem to be based on the solutions of smaller subproblems.

Modularity

the subdivision of a computer program into separate subprograms.

Function/Procedure

a named group of programming instructions that may have parameters and return values; also known as method or function.

Parameters

input variables of a function/procedure.

Arguments

specify the values of the parameters when a procedure is called.

Array or List

an ordered sequence of values.

Traversing

traversing a list can be complete traversal, where all elements in the list are accessed, or a partial traversal, where only a portion of elements are accessed.

Linear search (sequential search) algorithms

check each element of a list, in order, until the desired value is found or all elements in the list have been checked.

Binary search algorithms

starts at the middle of a sorted data set of numbers and eliminates half of the data; this process repeats until the desired value is found or all elements have been eliminated.

Software library

contains functions/procedures that may be used in creating new programs.

Application program interfaces (API)

are specifications for how programs, functions or procedures behave and can be used by other software.

Simulation

a representation that uses varying sets of values to reflect the changing state of a phenomenon.

Problem

a general description of a task that can (or cannot) be solved algorithmically.

Instance

specific input of a problem (ex: sorting is a problem; sorting the list (2, 3, 1, 7) is an instance of the problem.

Decision problem

problem with a yes/no answer (ex: is there a path from A to B?).

Optimization problem

problem with the goal of finding the "best" solution among many. (ex: what is the shortest path from A to B?)

Efficiency

an estimation of the amount of computational resources used by an algorithm; typically expressed as a function of the size of the input.

Reasonable amount of time

algorithms with a polynomial efficiency or slower (constant, linear, square, cube, etc.).

Unreasonable amount of time

algorithms with exponential or factorial efficiencies.

Heuristic

an approach to a problem that produces a solution that is not guaranteed to be optimal but may be used when techniques that are guaranteed to always find an optimal solution are impractical.

Decidable problem

a decision problem for which an algorithm can be written to produce a correct output for all inputs. (ex: "Is the number even?")

Undecidable problem

one for which no algorithm can be constructed that is always capable of providing a correct yes-or-no answer.