Mr Hylton J277 Unit 2

Abstraction

Removing the irrelevant details to simplify a tasks

Decomposition

Breaking a task down to a series of smaller tasks

Algorithmic Thinking

The process of solving problems using a series of steps.

Binary Search

An ordered list is divided in 2 with each comparison. The list must be sorted before

Linear Search

Starting at the beginning of the data set, each item of data is examined until a match is made or the end of the list is reached

Bubble Sort

Moving through a list repeatedly, comparing elements and swapping elements that are in the wrong order.

Merge Sort

Breaking your list down in to pairs, putting the pairs in order and then merging them together, each time, putting them in order

Insertion Sort

Each items is take in turn, compare to the items in a sorted list and placed in the correct position.

Line

Connects the objects

Process

Performs calculations, assigns and sets variables

Sub-program

Used to call or define a subprogram

Input/output

Used to take data in, print or return data

Decision

Used for if a decision needs to be make:

If or Loop

Terminal

Start/Stop

Pseudocode

An outline of the basic ideas behind how algorithms will work.

Flowchart

A diagram that shows step-by-step progression through a procedure or system especially using connecting lines and a set of conventional symbols.

Structure Diagram

A diagram used to display a decomposed problem. Each node becomes a sub program

Translator

Converts high level code to low level, machine code

Interpreter

Converts line by line. Does not create output code

Assembler

A program that translates an assembly-language program (e.g little man computer) into machine code. Uses an assembly table

Compiler

A program that translates code in a high-level language (such as Java) to machine code. Creates object code. E.g .exe file

high-level language

A programming language like Python that resembles natural language

low-level language

A programming language that is in machine code

Assembly Language

Programming language that has the same structure and set of commands as machine languages (mnemonics) but allows programmers to use symbolic representations of numeric machine code.

Integrated Development Environment (IDE)

Provides a developer with a way to create a program, run the program, and debug the program all within one application.

Editor

Somewhere to edit, create or write code

Error Diagnostics (/Debugging Tools)

Help find and fix errors in a program by telling the location of the errors and often suggests how to fix it

Run time environment

A feature of an IDE that allows you to run your code

Translator

A feature of an IDE that allows you code to be converted to a low level language

Features of an IDE

1) Editor

2) Error diagnostics

3) Run time environment

4) Translators

AND - Conjunction gate

Both inputs must be positive for a positive outcome

OR - Disjunction gate

At least one input must be positive for a positive outcome

NOT - Negation gate

Outputs the opposite of the input

Anticipating misuse

Expecting people to not use your program as intended. This could be malicious or not

Authentication

A method for confirming users' identities. E.g username and password

Comments

Adding notes to your code so that it is easier to maintain in the future and so that others can understand it.

indentation

Indenting/ tabbing your code in to show which part of a code if ran in which section. E.g If and loops in Python

Input Validation

Ensuring data input by the user meets specific criteria before processing. Range check. E.g. between 1 and 31. Type check. E.g. number not symbol. Presence check. E.g. data has been input. Format check. E.g. postcode is LLN(N) NLL.

Naming conventions

Making sure that all variable names and sub programme names are written in a specific forma. e.g all lowercase, all begin with var, so that others programmers can understand

Iterative Testing

This is testing the code as you create it

Final testing

Testing that is applied to what is believed to be the finished system

Testing

What is done to find errors with a programme or, check that it works

Test data

What you use to test a programme. E.g using 10 to check a year group field

Normal data

Test data that should be accepted

Erroneous data

Test data that should not be accepted

Boundary data

Testing the extremes of a range. E.g year group could be 7 and 13

Erroneous/Invalid test

Tests that should result in some sort of rejection. You do this to make sure invalid data is not accepted

Syntax Error

An error in the code which means the code cannot run

logical error

An error in the code which leads to an unexpected output. The code still runs

Sequence

Putting instructions in order to complete a task

Selection

Making a decision based on a test. e.g an IF

Iteration

when code is executed repeatedly

Count Controlled Iteration

A loop that uses a counter (typically the letter "I" in programming) to keep track of how many times the algorithm has iterated. E.g For Loop

Condition Controlled Iteration

A loop that will continue to iteration through an algorithm until a condition has been met. For example a While Loop

AND - Conjunction

^ Gives a positive output when both inputs are positive

OR - Disjunction

V Gives a positive output when at least 1 input is positive

NOT - Negation

¬ Outputs the opposite of the input

==

Equal to

!=

Not equal to

Less than or equal to

<

Less than

>=

Greater than or equal to

-

Subtraction

*

Multiplication

+

Addition

MOD Modulus

Returns the remainder

/

Division

DIV/Quotient

Returns only the integer of the division

^ Exponentiation

(to the power)

Integer

Data Type- Whole number

Real

Data Type- Decimal

Boolean

Data Type- True or False

Character

Data Type- A single keyboard character

String

Data Type- Several characters together

Open text file

variable=open("Text file name","open mode")

Read text file

New Variable= TextVariable.READ()

Write to a text file

TextVariable.Write(Text or variable)

Close text file

TextVariable.close()

record

A collection of arrays that appear as a row in a database or table.

SQL

Language for managing databases by typing commands.

*

Wild card used in databases. Means all

SELECT

SQL- States which fields to include

FROM

SQL- States which tables to get fields from

WHERE

SQL- Search criteria for SQL

Array

A variable that stores multiple items

variable name=[item 1,item 3,item 3]

print (variable name[0])

Variable

A labelled area of memory, that can be changed by the program

Constant

A labelled area of memory, that cannot be changed by the program

Functions/procedure/Sub programme/Subroutine

Re callable code written to perform a function

2D Array

variable name=[item 1,item 3,item 3],[item 1,item 3,item 3]

print(variable name[0,2]

Random number generation

import random

number=randbetween(0,10