National 5 Computing Science - Summary Notes PDF

Computer Systems ================ +-----------------------------------+-----------------------------------+ | | - Everything stored by a | | | computer is stored using | | | B...

Computer Systems ================ +-----------------------------------+-----------------------------------+ | | - Everything stored by a | | | computer is stored using | | | Binary -- 0 & 1 | | | | | | - 37 = | | | | | | 128 64 32 16 8 4 2 | | | 1 | | | ----- ---- ---- ---- --- --- -- | | | - --- | | | 0 0 1 0 0 1 0 | | | 1 | | | | | | - The mantissa and exponent are | | | stored as separate numbers. | | | The computer recreates the | | | number for calculations when | | | it needs to. | | | | | | | | | | | | - Each character is given an | | | 8-bit ASCII Code. | | | | | | - For example -- V = 86 = | | | 01010110 | | | | | | | | | | | | - Vector graphics store a | | | picture by storing each | | | objects attribute -- e.g. the | | | instructions to draw the | | | shape. | | | | | | - **Rectangle** - (height, | | | width, x, y, fill colour, | | | line colour) | | | | | | - **Ellipse** - (cx, cy, rx, | | | ry, fill colour, line colour) | | | | | | - **Line** - (x1, y1, x2, y2, | | | line colour) | | | | | | - **Polygon** - *any shape with | | | 3 of more sides* - (x1, y1, | | | x2, y2, x3, y3, fill colour, | | | line colour) | | | | | | | | | | | | - Computers stores, in binary, | | | each pixel. Number of bits | | | per pixel depends on the | | | number of colours in the | | | image -- more colours, more | | | bits. | +===================================+===================================+ | | - **Control Unit** -- controls | | | the sequencing of fetching, | | | decoding and executing | | | instructions. | | | | | | - **Arithmetic Logic Unit** -- | | | performs all calculations and | | | logical operations | | | | | | - **Registers** -- temporary | | | memory locations within the | | | processor. | | | | | | **Memory locations with unique | | | addresses** | | | | | | - All memory locations within | | | RAM is given a unique address | | | so that the computer can read | | | and write data to that | | | location correctly. | | | | | | **Buses** | | | | | | - **Address Bus** -- this | | | identifies the memory | | | location that is going to | | | read from or written to. | | | | | | - **Data Bus** -- this | | | transfers the data between | | | the processor and memory, and | | | vice-versa. | | | | | | | | | | | | - **Interpreter** -- translates | | | the program one line at a | | | time into machine code and | | | executes immediately. Machine | | | code is not retained, so must | | | be translated each time. | | | | | | - Good for testing, errors are | | | highlighted straight away. | | | | | | - **Compiler** -- translate | | | whole program, and then save | | | machine code version. | | | Translate code can be run | | | again, and again. Used for | | | programs that are ready for | | | release. | +-----------------------------------+-----------------------------------+ | | - It is estimated that two | | | billion computer systems are | | | in use in the world -- these | | | all use energy. As user we | | | need to consider how to | | | reduce unnecessary energy | | | use. | | | | | | | | | | | | - **Settings on monitors** -- | | | reduce brightness, activate | | | efficiency mode, use energy | | | efficient monitors. | | | | | | - **Power down settings** -- | | | power-down after a period of | | | inactivity, control setting | | | for single components. | | | | | | - **Leaving computers on | | | standby** -- power | | | consumption is reduced. | +-----------------------------------+-----------------------------------+ | | - A firewall protects against | | | suspicious access to a | | | computer. When an external | | | computer tries to access a | | | computer, the firewall | | | decides if the external | | | computers access should be | | | granted or denied. | | | | | | | | | | | | - Encryption codes the | | | information so that if it is | | | intercepted then they would | | | not be able to make sense of | | | it. It can only be understood | | | by the sender and received. | +-----------------------------------+-----------------------------------+ Website Design & Development ============================ +-----------------------------------+-----------------------------------+ | | - **End-user** -- describes the | | | group of people most likely | | | to use the website. E.g. | | | Children, employees, etc. | | | | | | - **Functional requirements** | | | -- things that the website | | | must be able to do e.g. | | | Search a database. | +===================================+===================================+ | | - **Linear** -- users move from | | | one page to another in | | | sequence | | | | | | - **Hierarchical --** pages are | | | accessed dependent upon their | | | position within the | | | hierarchy. | | | | | | **Wireframing is used to design | | | the visual layout of a web page. | | | Wireframing should clearly | | | show:** | | | | | | - **navigational links** | | | | | | - ***Internal*** links take | | | the user to another page | | | within site,\ | | | ***External*** links take | | | the user to a different | | | site. | | | | | | - ***Absolute*** address | | | gives the full URL, *\ | | | **Relative*** address | | | give URL based on current | | | location. | | | | | | | | | | | | - **consistency across multiple | | | pages:** | | | | | | All pages of website should | | | follow the same design rules, | | | so that the user knows what | | | to expect. | | | | | | - **relative vertical | | | positioning of the media | | | displayed** -- where text, | | | graphics audio & video will | | | be placed. | | | | | | - **file formats of the media | | | (text, graphics, video, and | | | audio)** -- see next page | | | | | | | | | | | | - The text, graphics, video and | | | audio contained within this | | | website are protected. | | | | | | - The user is prevented from | | | making, using or distributing | | | copies without the owner's | | | permission. | +-----------------------------------+-----------------------------------+ | | **Compare a range of standard | | | file formats:** | | | | | | - **Audio:** | | | | | | - **wav** -- uncompressed, | | | high quality, large file | | | size. | | | | | | - **mp3** -- lossy | | | compression, good | | | quality, smaller file | | | size. | | | | | | - **Graphics** | | | | | | - **jpeg** -- lossy | | | compression, transparency | | | & animation not supported | | | | | | - **gif** -- lossless | | | compression, animation & | | | transparency supported, | | | 8-bit colour. | | | | | | - **png** -- lossless | | | compression, animation & | | | transparency supported, | | | 48-bit colour | | | | | | **Describe the factors affecting | | | file size and quality:** | | | | | | - **Graphic Resolution** -- the | | | more pixels per inch, the | | | better the quality, but the | | | larger the file size. | | | | | | | | | | | | - **Colour Bit Depth** -- more | | | bits per colour, more | | | colours, but a larger file | | | size. | | | | | | - **Sampling Rate** - the more | | | samples taken per second, | | | more realistic the audio, but | | | the larger the file size | | | | | | **Describe the need for | | | compression.** | | | | | | - Compression is the process of | | | reducing the size of a file. | | | Compression is needed to save | | | backing storage, or the time | | | used to send the file between | | | two computers i.e. over the | | | internet. | | | | | | | | | | | | - A prototype is a draft of the | | | interface that is produced | | | early in the development | | | process. It should closely | | | resemble the intended look | | | and feel of the final product | | | so user of it get a good idea | | | of the finished product. | +-----------------------------------+-----------------------------------+ | | **Describe, exemplify and | | | [implement] Cascading | | | Style Sheets (CSS):** | | | | | | CSS is used to define the | | | colours, fonts and layout of web | | | page content. | | | | | | **Internal & External CSS** | | | | | | - **Internal** **Stylesheet** | | | holds the CSS code for the | | | webpage in the \ | | | section of an HTML file. | | | | | | - **External Stylesheet** holds | | | the CSS code in a separate | | | CSS file, which is liked to | | | an HTML document. | | | | | | - **Selectors** -- the html | | | elements that you want to | | | style. In the example below | | | H1 | | | | | | H1 {color: blue; font-size: | | | 12px;} | | | | | | - **ID ­**-- when writing HTML | | | it is possible to give an | | | element its own unique ID, | | | CSS can then be applied to | | | it. An ID can only be used | | | once in an HTML document. | | | | | | - HTML - \ | | | Introduction Paragraph | | | \ | | | | | | - CSS - \#intro {color: | | | black; font-family: | | | verdana;} | | | | | | - **Class** -- worked similar | | | to an ID, but can be applied | | | to multiple HTML tags. | | | | | | - HTML - \ This is | | | important \ | | | | | | - CSS -.important | | | {background-color: | | | yellow; text-align: | | | center;**}** | +-----------------------------------+-----------------------------------+ | | **Describe and identify | | | Javascript coding related to | | | mouse events:** | | | | | | Using JavaScript, functions are | | | created that will change what | | | appears on screen dependant on | | | what the user does with the | | | mouse. | | | | | | Line 1: \ | | | | | | Line 2: function mouseOver() { | | | | | | Line 3: | | | document.getElementById(\"demo\") | | |.style.color | | | = \"red\"; | | | | | | Line 4: } | | | | | | Line 5: function mouseOut() { | | | | | | Line 6: | | | document.getElementById(\"demo\") | | |.style.color | | | = \"black\"; | | | | | | Line 7: } | | | | | | Line 8: \ | | | | | | Line 2-4 -- when the mouse it | | | over and element with the ID | | | "demo" the colour will change to | | | red. | | | | | | Lines 5-6 -- when the mouse it | | | moved away from the above element | | | the colour will change to black. | +-----------------------------------+-----------------------------------+ | | **Describe, exemplify and | | | implement HTML code:** | | | | | | - **\... \** - | | | tells the browser the rest of | | | the document contains HTML | | | | | | - **\... \** - | | | contains information about | | | the page itself -- including | | | CSS | | | | | | - **\... | | | \** - title of the | | | webpage, appears on browser | | | tabs. | | | | | | - **\... \** - | | | page content is placed | | | between these tags. | | | | | | - **\... \** - | | | creates a heading, there are | | | six different sizes (h1 to | | | h6) | | | | | | - **\... \** - | | | defines a paragraph | | | | | | - **\... \** - | | | used so CSS can be applied to | | | a group of elements | | | | | | - **\ | | | link text \** - creates | | | a hyperlink -- can take user | | | to different page/ website | | | | | | - **\** - inserts an image. | | | | | | - **\ \ \** - | | | inserts an audio file | | | | | | - **\ \ \** - | | | inserts a video file | | | | | | - **lists** | | | | | | - **\... \** - | | | creates an ordered list - | | | numbered | | | | | | - **\... \** - | | | created an un-ordered | | | list -- bulleted | | | | | | - **\... \** - | | | adds a list item | | | | | | **Describe and implement | | | hyperlinks (internal and | | | external), relative and absolute | | | addressing.** | | | | | | See above | | | | | | **Read and explain code that | | | makes use of the above HTML.** | +-----------------------------------+-----------------------------------+ | | **Describe and exemplify | | | testing:** | | | | | | - **matches user-interface | | | design** -- does it match the | | | wireframe design and | | | prototype. | | | | | | - **links and navigation work | | | correctly** -- when links are | | | clicked do they take you to | | | the correct location | | | | | | - **media (such as text, | | | graphics, and video) display | | | correctly** -- are they in | | | the correct place, do they | | | work | | | | | | - **consistency** -- do all | | | pages follow a similar | | | design. External CSS may | | | mitigate this. | +-----------------------------------+-----------------------------------+ | | **Evaluate solution in terms of | | | fitness for purpose** | | | | | | - Does the website meet the | | | end-user and functional | | | requirements? | | | | | | - Yes -- then website is | | | fit for purpose | | | | | | - No -- revisit previous | | | phases in the development | | | process | +-----------------------------------+-----------------------------------+ Database Design & Development ============================= +-----------------------------------+-----------------------------------+ | | **Identify the end-user and | | | functional requirements of a | | | database problem that relates to | | | the implementation at this | | | level.** | | | | | | - **end-user** -- what does the | | | end user want to able to do | | | with the database e.g. search | | | for student data | | | | | | - **functional requirements** | | | -- the tasks the database | | | should perform/ data it | | | should hold e.g. first name | +===================================+===================================+ | | - they have prior consent of | | | data subject (the person the | | | data is about) to store | | | personal information | | | | | | - the data is accurate and | | | up-to-day | | | | | | - the data used for limited, | | | specifically stated purposes | | | | | | - the data kept safe and secure | | | | | | | | | | | | - **Entity** -- a place where | | | information about a person, | | | thing or concept is collected | | | -- a table. | | | | | | - **Attribute** -- describe the | | | facts, details or | | | characteristic of an entity | | | -- a field. | | | | | | **An Entity-Relationship diagram | | | shows the relationship that | | | exists between two entities.** | | | | | | Machine generated alternative | | | text: Primary Key Uniquely | | | identified each record in this | | | table. ACTIVITY Activity ID Title | | | Age Range Venue Teacher ID\* | | | Foreign Key TEACHER Teacher ID | | | Name Teaching Room Subject | | | Primary Key Uniquely identified | | | each record in this table. Uses | | | to link this table to the other. | | | It\'s the Primary Kev in the | | | other table. | | | | | | *Table: Customers* | | | ------------------ | | | | | | **Field** **Key** * | | | *Attribute Type** **Required** | | | **Validation** | | | --------------- ------------- - | | | ------------------- ------------- | | | - ------------------------------- | | | --------- | | | Customer\_ID Primary Key N | | | umber Yes | | | Length = 3 | | | Title   T | | | ext Yes | | | Restricted Choice = Mr, Mrs, Mi | | | ss, Ms, | | | First Name   T | | | ext Yes | | |   | | | Surname   T | | | ext Yes | | |   | | | Flight Date   D | | | ate Yes | | |   | | | First Class   B | | | oolean No | | |   | | | Flight Number Foreign Key T | | | ext Yes | | | Restricted Choice | | | | | | **Attribute Types:** | | | | | | - **Text** -- a combination of | | | text and number e.g. name, | | | address, telephone number. | | | | | | - **Number** -- whole numbers | | | and decimal numbers. | | | | | | - **Date** | | | | | | - **Time** | | | | | | - **Boolean** -- true or false | | | | | | **Validation** -- ensure data is | | | allowable and sensible, makes it | | | more difficult to make mistakes. | | | | | | - **Range** -- ensures data if | | | between a lower and upper | | | limit | | | | | | - **Restricted Choice** -- | | | limits the user to a list of | | | options. | | | | | | - **Length Check** -- restricts | | | the number of characters that | | | can be entered. | | | | | | - **Presence Check** -- ensures | | | that the field is not left | | | blank -- it is required | +-----------------------------------+-----------------------------------+ | | **Implement relational databases | | | with two linked tables, to match | | | the design with referential | | | integrity.** | | | | | | Referential integrity ensures | | | that the foreign key value has a | | | matching value in the | | | corresponding primary key. | | | | | | **Describe, exemplify and | | | implement SQL operations for | | | pre-populated relational | | | databases.** | | | | | | SQL standard for Structured Query | | | Language, it is used to | | | interrogate the data held in a | | | database. | | | | | | **SELECT... FROM...** -- is | | | used to select data from the | | | database -- SELECT name, gender | | | FROM student; | | | | | | **... WHERE** -- where is used to | | | ensure that only records that | | | meet a specific condition are | | | returned. | | | | | | SELECT name, gender FROM student | | | WHERE regClass = "1S1"; | | | | | | **\... ORDER BY** -- used to | | | order the results in either | | | ascending or descending order. | | | ORDER BY age ASC | | | | | | SELECT firstname, surname, gender | | | | | | FROM student | | | | | | WHERE regClass = "1S1" | | | | | | ORDER BY surname ASC; | | | | | | **INSERT INTO** -- is used to add | | | a record to a table.\ | | | INSERT INTO Pupil | | | | | | VALUES (Ben, Simon, Male, | | | 10/10/05, 1S1); | | | | | | **UPDATE** -- is used to update a | | | current record held in the | | | database. The WHERE identifies | | | specific records. | | | | | | UPDATE pupil | | | | | | SET Reg Teacher = "Dr. G. Wilson" | | | | | | WHERE Reg Teacher = "Mr E. Neil" | | | | | | **DELETE** -- delete a record | | | from the database. No WHERE will | | | mean all content is deleted from | | | the table. | | | | | | DELETE FROM pupil | | | | | | WHERE firstName = "Eva" AND | | | surname = "Forrest"; | | | | | | **EQUI-JOIN** -- used to display | | | result from two different tables. | | | Requires Primary Key & Foreign | | | Key to be linked | | | | | | SELECT firstname, surname, | | | instrument | | | | | | FROM student, musicTution | | | | | | WHERE student.studentCode = | | | musicTution.studentCode AND year | | | \< 4: | | | | | | *List the name and instrument | | | played by all pupils in S1-3* | | | | | | **Operators** | | | | | | - **AND** -- both conditions | | | must be true - WHERE regClass | | | = "1S1" AND gender= "female"; | | | | | | - **OR** -- either condition | | | must be true - WHERE year = | | | "1" OR year= "2"; | | | | | | - **\** - greater than - WHERE | | | year \> 3; | | | | | | **Read and explain code that | | | makes use of the above SQL.** | +-----------------------------------+-----------------------------------+ | | **Describe and exemplify testing | | | SQL operations work correctly at | | | this level** | | | | | | - When testing queries, it is | | | good practice to document | | | expected results and actual | | | results. | | | | | | A comparison can then be | | | made, with testing passed if | | | the expected result and | | | actual result is the same. | +-----------------------------------+-----------------------------------+ | | **Evaluate solution in terms of | | | fitness for purpose & accuracy of | | | output** | | | | | | - A database is deemed fit for | | | purpose if it meets the | | | requirements determined at | | | the analysis stage. If the | | | database is not fit for | | | purpose, it will be necessary | | | to revisit previous phases of | | | the development process. | +-----------------------------------+-----------------------------------+ Software Design & Development ============================= +-----------------------------------+-----------------------------------+ | | **Describe and implement the | | | phases of an iterative | | | development process:** | | | | | | - **Analysis** -- production of | | | a software specification that | | | will outline what the | | | software must do | | | | | | - **Design** -- plan the design | | | of the program, and the user | | | interface | | | | | | - **Implementation** -- write | | | the code for the program/ | | | software | | | | | | - **Testing** -- fully test the | | | program/ software to ensure | | | that all aspect work | | | correctly | | | | | | - **Documentation** -- | | | technical guide -- how to | | | install software - and user | | | guide -- how to work the | | | software. | | | | | | - **Evaluation** -- is the | | | program fit for purpose and | | | robust | | | | | | This is an iterative process -- | | | each stage may have to be | | | revisited as a result of new | | | information coming to light. | +===================================+===================================+ | | - **Inputs** -- data that is | | | entered into the program. | | | | | | - **Processes** -- what the | | | program does with the | | | inputted data. | | | | | | - **Output** -- data that is | | | outputted to the user. | +-----------------------------------+-----------------------------------+ | | - **Structure diagrams** -- | | | breaks the problems down into | | | smaller sections. | | | | | | - **Flowcharts** -- shows what | | | is going on in a program and | | | how data flows around it. | | | | | |  | | | | | | - **Pseudocode** -- structured | | | English for describing a | | | program, read by a human | | | | | | **get age from user** | | | | | | **if age \< 15?** | | | | | | **Send discount to user** | | | | | | **else** | | | | | | **Send no discount to user** | | | | | | **end if** | +-----------------------------------+-----------------------------------+ | | - **Data types** | | | | | | - **string** -- stores text | | | and alphanumeric | | | combinations e.g. | | | Sausage, AB12 4RT | | | | | | - **character** -- stores a | | | single character which | | | can be a letter, number | | | or symbol e.g. Q. \#, 6 | | | | | | - **integer** -- stores | | | positive and negative | | | whole numbers e.g. 17. | | | -45. 124 | | | | | | - **real** -- stores | | | numbers with decimal | | | places, can also store | | | integers e.g. 3.14, - | | | 5.67 | | | | | | - **boolean** -- stores | | | TRUE or FALSE only. | | | | | | - **Data structures -** | | | | | | - **arrays** -- stores a | | | list of related data e.g. | | | names of pupils in a | | | class.\ | | | Image result for arrays | | | programming | +-----------------------------------+-----------------------------------+ | | **Describe, exemplify, and | | | implement the appropriate | | | constructs in a high-level | | | language:** | | | | | | - **Assigning values to | | | variables**. | | | | | | Variables are locations in | | | memory where programs store | | | and retrieve information. | | | | | | SET score TO 5 | | | | | | SET score TO score + 12 | | | | | | SEND score TO DISPLAY → 17 | | | will be outputted to the | | | user. | | | | | | - **Arithmetic operations** | | | | | | - **addition** -- SET | | | answer TO a + b | | | | | | - **subtraction** -- SET | | | answer TO a -- b | | | | | | - **multiplication** -- SET | | | answer TO a \* b | | | | | | - **division** -- SET | | | answer TO a -- c | | | | | | - **exponentiation** -- *to | | | the power off **--*** SET | | | answer TO a\^b *e.g. 2\^3 | | | = 8* | | | | | | - **Concatenate strings -** | | | concatenation is the process | | | of joining two or more | | | strings together to make a | | | new text string. SET | | | displayName to firstName | | | **&** surname. | | | | | | - **Selection -** The program | | | selects an action dependant | | | upon the value of variables | | | held in the program | | | | | | - **If... Then** -- IF | | | *condition* THEN *action* | | | END IF | | | | | | - **If...** **Then... | | | Else** -- IF *condition* | | | THEN *action\_a* ELSE | | | *action\_b* END IF | | | | | | - **If...** **Then... | | | Else If** -- IF | | | *condition\_1* THEN | | | *action\_a* ELSE IF | | | condition\_2 THEN | | | action\_b END IF | | | | | | - **Conditional Statements** | | | | | | - **Simple Conditions** -- | | | depends on one | | | conditional statement | | | being true. | | | | | | Operator Explanation | | | Example | | | ---------- -------------------- | | | ----- ------------ | | | \< Less than | | | age \< 18 | | | \> More than | | | age \> 18 | | | \= 18 | | | = or == Equality | | | age == 18 | | | ≠ or != Inequality/Not equal | | | to age != 18 | | | | | | - **Complex Conditions** | | | | | | - **AND** -- both | | | conditions must be true | | | e.g. gender = "M" AND | | | age \> 18 | | | | | | - **OR** -- either of the | | | conditions must be true | | | e.g. class = 1 OR class = | | | 3 | | | | | | - **NOT** -- the condition | | | should not be true e.g. | | | NOT (gender = "M") | +-----------------------------------+-----------------------------------+ | | - **Iteration and | | | repetition -** Iteration is | | | the process where program | | | repeat a group of | | | instructions. | | | | | | - **Fixed Loop** -- when a | | | group of instructions is | | | repeated a pre-determined | | | number of times. | | | | | | FOR counter 0 TO 5 DO | | | | | | SEND "I must behave" TO | | | DISPLAY | | | | | | End For | | | | | | - **Conditional Loop** -- | | | will keep repeating a | | | group of instructions | | | until a specific | | | conditional is met. | | | | | | GET password FROM | | | (STRING) KEYBOARD | | | | | | WHILE password != | | | "letmein" DO | | | | | | SEND "In-correct" TO | | | DISPLAY | | | | | | GET password FROM | | | (STRING) KEYBOARD | | | | | | END WHILE | | | | | | - **Predefined functions (with | | | parameters):\ | | | **A pre-defined function is a | | | segment of code that can be | | | referred to and it will do | | | something useful. | | | | | | - **Round** -- rounds a | | | value to a specific | | | number of decimal places. | | | | | | SET pi TO 13.141592 | | | | | | SET pi TO ROUND (pi, 2) | | | *→ the new value of pi | | | will be 13.14* | | | | | | - **Length** -- give the | | | number of character | | | present in a variable. | | | | | | SET word TO "Mississippi" | | | | | | SET numWord TO LENGTH | | | (word) *→ the value of | | | numWord would be 11* | | | | | | - **Random** -- generates a | | | random number, between a | | | lower and upper range. | | | | | | SET bonusBall to RANDOM | | | (1,59) | +-----------------------------------+-----------------------------------+ | | **Describe, exemplify, and | | | implement standard algorithms:** | | | | | | - | | | | | | +--------------+--------------+ | | | | GET score | *Get initial | | | | | FROM | score from | | | | | (INTEGER) | the user* | | | | | KEYBOARD | | | | | | | *Check if | | | | | WHILE score | data if | | | | | \< 1 or | valid, if | | | | | score \> 100 | invalid then | | | | | DO | enter loop* | | | | | | | | | | | SEND | *Display | | | | | "In-Valid" | error | | | | | TO DISPLAY | message* | | | | | | | | | | | GET score | *Get new | | | | | FROM | score from | | | | | (INTEGER) | user* | | | | | KEYBOARD | | | | | | | *Repeat loop | | | | | END WHILE | until data | | | | | | is valid* | | | | +--------------+--------------+ | | | | | | - | | | | | | +--------------+--------------+ | | | | SET total TO | *Set the | | | | | 0 | initial | | | | | | total to 0* | | | | | FOR counter | | | | | | 0 TO 5 | *Fixed loop, | | | | | | 5 times.* | | | | | GET | | | | | | itemPrice | *Receive | | | | | FROM (REAL) | item price | | | | | KEYBOARD | from the | | | | | | user.* | | | | | SET total = | | | | | | total + | *Add the | | | | | itemPrice | item price | | | | | | to the | | | | | END FOR | total* | | | | | | | | | | | | *End Loop* | | | | +--------------+--------------+ | | | | | | - **Traversing a 1-D array** -- | | | to transverse an array means | | | to access each element stored | | | in the array so that the data | | | can be checked or used as | | | part of a process. | | | | | | *A program is required to | | | count all A grades.* | | | | | | +--------------+--------------+ | | | | SET grade TO | *Array with | | | | | \[A, B, C, | all grades* | | | | | A, A, B, A, | | | | | | C\] | *Number to A | | | | | | grades | | | | | SET numA TO | counted* | | | | | 0 | | | | | | | *Fixed loop, | | | | | FOR counter | loop for | | | | | 0 TO 7 | each item in | | | | | | array* | | | | | IF | | | | | | grade\[count | *Check the | | | | | er\] | grade at | | | | | == "A" THEN | index if it | | | | | | an a* | | | | | numA = numA | | | | | | + 1 | *Then count | | | | | | the A* | | | | | END FOR | | | | | | | *End Loop* | | | | +--------------+--------------+ | +-----------------------------------+-----------------------------------+ | | **Describe, identify, exemplify, | | | and implement normal, extreme, | | | and exceptional test data.** | | | | | | The purpose of testing is to | | | detect and remove errors in a | | | program. Programs should be | | | comprehensively tested to see | | | whether they give the correct | | | results when dealing with normal, | | | extreme and exceptional test | | | data. | | | | | | - **Normal** -- data that you | | | would expect to work or be | | | accepted | | | | | | - **Extreme** -- data at the | | | lower and upper limits of | | | what is expected. | | | | | | - **Exceptional** -- data that | | | should not be accepted by the | | | program. | | | | | | - **Test Table** -- provide a | | | structure to testing, and | | | evidence that testing has | | | taken place. | | | | | |  | | | | | | As one test has failed, the | | | programmer should now review | | | the code to identify why this | | | test has failed\ | | | -- and rectify the error. | | | | | | **Describe and identify | | | syntax, execution, and logic | | | errors.** | | | | | | | | | | | | - **Syntax** -- This is an | | | error in the spelling or | | | grammar used when coding.\ | | | For example, misspelt command | | | words, missing brackets, | | | commands or colons.\ | | | Syntax errors are identified | | | by the interpreter, as the | | | code will not run. | | | | | | - **Execution** -- This type of | | | error occurs when the program | | | is asked to do something that | | | it cannot, resulting in a | | | crash. For example, dividing | | | by zero or trying to store a | | | string a integer variable. | | | | | | - **Logic** -- This is an error | | | in the logic of the code e.g. | | | using a \< instead of \>. The | | | program will run, but it will | | | produce unexpected results. | | | Logic errors are usually only | | | resolved by carrying out | | | testing. | +-----------------------------------+-----------------------------------+ | | **Describe, identify, and | | | exemplify the evaluation of a | | | solution in terms of:** | | | | | | - - - **use of loops** | | | --repeating instructions | | | is more efficient than a | | | sequence of individual | | | instructions. | | | | | | - **arrays** -- using | | | arrays to store related | | | data is more efficient | | | than using multiple | | | variables. | | | | | | - **nested IFs** -- using | | | IF... ELSE IF... is | | | more efficient that using | | | multiple IF... THEN | | | | | | - - - **internal | | | commentary** -- add | | | descriptions, notes and | | | explanation to the code. | | | | | | - **meaningful | | | identifiers** -- use | | | variable names that | | | describe what the | | | variable contains. | | | | | | - **indentation --** makes | | | it easier to identify | | | constructs. Mandatory in | | | Python. | | | | | | - **white space** -- help | | | makes it clearer where | | | code is placed. | +-----------------------------------+-----------------------------------+