document_title: AP Computer Science A

question_text: when is the last time for the gridworld case study to be tested

text: AP Computer Science A

text: Course content[edit]

text: AP Computer Science A emphasizes object-oriented programming methodology with an emphasis on problem solving and algorithm development. It also includes the study of data structures and abstraction, but these topics were not covered to the extent that they were covered in AP Computer Science AB. The Microsoft-sponsored program Technology Education and Literacy in Schools (TEALS) aims to increase the number of students taking AP Computer Science classes.[3]

text: Topics covered by the course include:[4][5]

text:
Object-Oriented Program Design

Program Design

Read and understand a problem's description, purpose, and goals.
Specify the purpose and goals for a problem. (AB only)
Apply data abstraction and encapsulation.
Read and understand class specifications and relationships among the classes ("is-a", "has-a" relationships).
Decompose a problem into classes, define relationships and responsibilities of those classes. (AB only)
Understand and implement a given class hierarchy.
Identify reusable components from existing code using classes and class libraries.

Class Design

Design and implement a class.
Design and implement a set of interacting classes. (AB only)
Design an interface.
Choose appropriate data representation and algorithms.
Choose appropriate advanced data structures and algorithms. (AB only)
Apply functional decomposition.
Extend a given class using inheritance.

Program Implementation

Implementation techniques

Methodology

Object-oriented development
Top-down development
Encapsulation and information hiding
Procedural abstraction

Programming constructs

Primitive types vs. objects
Declaration

Constant declarations
Variable declarations
Class declarations
Interface declarations
Method declarations
Parameter declarations

Console output (System.out.print/println)
Control

Methods
Sequential
Conditional
Iterations
Recursion

Java library classes (included in the A or AB-level AP Java Subset)

Program Analysis

Testing

Test classes and libraries in isolation
Identify boundary cases and generate appropriate test data
Perform integration testing

Debugging

Categorize errors: compile time, runtime, logic
Identify and correct errors
Techniques: use a debugger, add extra output statements, hand-trace code

Understand and modify existing code
Extend existing code using inheritance
Understand error handling

Understand runtime exceptions
Throw runtime exceptions (AB only)

Reason about programs

Preconditions and postconditions
Assertions
Invariants (AB only)

Analysis of algorithms

Informal comparisons of running times
Exact calculation of statement execution counts
Big O notation (AB only)
Worst-case and average-case time and space analysis (AB only)

Numerical representations and limits

Representations of numbers in different bases
Limitations of finite representations (e.g., integer bounds, imprecision of floating-point representations, and round-off error)

Standard Data Structures

Simple data types (int, boolean, double)
Classes
One-dimensional arrays
Two-dimensional arrays
Linked lists (singly, doubly, circular) (AB only)
Stacks (AB only)
Queues (AB only)
Trees (AB only)
Heaps (AB only)
Priority queues (AB only)
Sets (AB only)
Maps (AB only)

Standard Algorithms

Operations on data structures listed above

Traversals
Insertions
Deletions
Iterators (AB only)

Searching

Sequential
Binary
Hashing (AB only)

Sorting

Selection
Insertion
Mergesort
Quicksort (AB only)
Heapsort (AB only)

Computing in Context

Major hardware components

Primary and secondary memory
Processors
Peripherals

System software

Language translators/compilers
Virtual machines
Operating systems

Types of systems

Single-user systems
Networks

Responsible use of computer systems

System reliability
Privacy
Legal issues and intellectual property
Social and ethical ramifications of computer use

text: Case studies and labs[edit]

text: Historically, the AP exam used several programs in its free-response section to test students' knowledge of object-oriented programs without requiring them to develop an entire environment. These programs were called Case Studies.

text: This practice was discontinued as of the 2014-15 school year and replaced with optional labs that teach concepts.

text: Case studies (discontinued)[edit]

text: Case studies were used in AP Computer Science curriculum starting in 1994.[6]

text: Big Integer case study (1994-2000)[edit]

text: The Big Integer case study was in use prior to 2000. It was replaced by the Marine Biology case study.

text: Marine Biology case study (2000-2007)[edit]

text: The Marine Biology Case Study (MBCS) was a program written in C++ until 2003, then in Java, for use with the A and AB examinations. It served as an example of object-oriented programming (OOP) embedded in a more complicated design project than most students had worked with before.

text: The case study was designed to allow the College Board to quickly test a student's knowledge of object oriented programming ideas such as inheritance and encapsulation while requiring students to understand how objects such as "the environment", "the fish", and the simulation's control module interact with each other without having to develop the entire environment independently, which would be quite time consuming. The case study also gives all students taking the AP Computer Science exams with a common experience from which to draw additional test questions.

text: On each of the exams, at least one free-response question was derived from the case study. There were also five multiple-choice questions that are derived from the case study.

text: This case study was discontinued from 2007, and was replaced by GridWorld.

text: GridWorld case study (2008-2014)[edit]

text: GridWorld is a computer program case study written in Java that was used with the AP Computer Science program from 2008 to 2014.[7] It serves as an example of object-oriented programming (OOP). GridWorld succeeded the Marine Biology Simulation Case Study, which was used from 2000–2007. The GridWorld framework was designed and implemented by Cay Horstmann, based on the Marine Biology Simulation Case Study. The narrative was produced by Chris Nevison and Barbara Cloud Wells, Colgate University.

text: The GridWorld Case Study was used as a substitute for writing a single large program as a culminating project. Due to obvious time restraints during the exam, the GridWorld Case Study was provided by the College Board to students prior to the exam. Students were expected to be familiar with the classes and interfaces (and how they interact) before taking the exam. The case study was divided into five sections, the last of which was only tested on the AB exam. Roughly five multiple-choice questions in Section I were devoted to the GridWorld Case Study, and it was the topic of one free response question in Section II.

text: GridWorld has been discontinued and replaced with a set of labs for the 2014-2015 school year.

text:
Actors

The GridWorld Case Study employs an Actor class to construct objects in the grid. The Actor class manages the object's color, direction, location, what the object does in the simulation, and how the object interacts with other objects.
Actors are broken down into the classes "Flower", "Rock", "Bug", and "Critter", which inherit the Actor class and often override certain methods (most notably the Act method). Flowers can't move, and when forced to Act, they become darker. Flowers are dropped by Bugs and eaten by Critters. Rocks are also immobile and aren't dropped or eaten. Bugs move directly ahead of themselves, unless blocked by a rock or another bug, in which case the Bug will make a 45 degree turn and try again. They drop flowers in every space they occupy, eat flowers that are directly on their space of grid, and are consumed by Critters. Critters move in a random direction to a space that isn't occupied by a Rock or other Critter and consume Flowers and Bugs.

Extensions

The Case Study also includes several extensions of the above classes. "BoxBug" extends "Bug" and moves in a box shape if its route is not blocked. "ChameleonCritter" extends "Critter" and does not eat other Actors, instead changing its color to match the color one of its neighbors. "Crab Critter" moves left or right and only eats Actors in front of it, but otherwise extends the "Critter" class.
Students often create their own extensions of the Actor class. Some common examples of student created extensions are Warden organisms and SimCity-like structures, in which objects of certain types create objects of other types based on their neighbors (much like Conway's Game of Life). Students have even created versions of the games Pac-Man, Fire Emblem, and Tetris.[8]

Known issues

The version that is available at the College Board website, GridWorld 1.00, contains a bug (not to be confused with the Actor subclass Bug) that causes a SecurityException to be thrown when it is deployed as an applet. This was fixed in the "unofficial code" release on the GridWorld website. Also, after setting the environment to an invalid BoundedGrid, it will cause a NullPointerException.

text: Labs[edit]

text: Instead of the discontinued case studies, the College Board created three new labs that instructors are invited to use, but they are optional and are not tested on the exam. There are no question on the specific content of the labs on the AP exam, but there are questions that test the concepts developed in the labs. The three labs are:[9]

text:
The Magpie Lab
The Elevens Lab
The Picture Lab

text: AP test[edit]

text: History[edit]

text: The AP exam in Computer Science was first offered in 1984.

text: Before 1999, the AP exam tested students on their knowledge of Pascal. From 1999 to 2003, the exam tested students on their knowledge of C++ instead. Since 2003, the AP Computer Science exam has tested students on their knowledge of computer science through Java.

text: Format[edit]

text: The exam is composed of two sections, formerly consisting of the following times:

text:
Section I: Multiple Choice [1 hour and 15 minutes for 40 multiple-choice questions]
Section II: Free-Response [1 hour and 45 minutes for 4 problems involving extended reasoning]

text: As of 2015, however, the Multiple Choice section was extended by 15 minutes while the Free-Response section was reduced by 15 minutes for the following:

text:
Section I: Multiple Choice [1 hour and 30 minutes for 40 multiple-choice questions]
Section II: Free-Response [1 hour and 30 minutes for 4 problems involving extended reasoning]

text: Grade distributions for AP Computer Science A[edit]

text: In the 2014 administration, 39,278 students took the exam. The mean score was a 2.96 with a standard deviation of 1.55. The grade distributions since 2003 were:

text:
Score
2003
2004
2005[10]
2006[11]
2007[12]
2008
2009[13]
2010
2011
2012[14]
2013[15]
2014[16]
2015[17]
2016[18]
2017[19]

5
17.1%
18.6%
17.9%
21.9%
19.3%
21.7%
23.2%
26.3%
24.9%
23.6%
26.6%
21.3%
24.4%
20.7%
24.4%

4
24.5%
23.6%
23.2%
22.2%
22.8%
21.7%
25.7%
24.7%
24.8%
24.3%
26.6%
23.1%
24.6%
20.4%
20.9%

3
19.6%
15.3%
14.9%
14.4%
14.5%
13.9%
13.2%
13.9%
14.2%
15.6%
13.9%
16.8%
15.3%
23.2%
21.9%

2
9.2%
9.4%
9.9%
7.7%
9.5%
9.0%
8.2%
7.9%
7.9%
7.7%
7.0%
7.7%
7.1%
12.5%
11.5%

1
29.6%
33.1%
34.0%
33.7%
33.9%
33.7%
29.8%
27.1%
28.2%
28.7%
25.9%
31.1%
28.6%
23.2%
21.3%

Mean
2.90
2.85
2.81
2.91
2.84
2.89
3.04
3.15
3.10
3.06
3.21
2.96
3.09
3.04
3.16

Students
14,674
14,337
13,924
14,662
15,049
15,537
16,622
20,120
22,176
26,103
31,117
39,278
48,994 [20]
57,937

text: AP Computer Science AB[edit]

text: Course content[edit]

text: The discontinued AP Computer Science AB course included all the topics of AP Computer Science A, as well as a more formal and a more in-depth study of algorithms, data structures, and data abstraction. For example, binary trees were studied in AP Computer Science AB but not in AP Computer Science A. The use of recursive data structures and dynamically allocated structures were fundamental to AP Computer Science AB. Due to low numbers of students taking the AP Computer Science AB exam, it was discontinued after the 2008–2009 year.[21]

text: Grade distributions for AP Computer Science AB[edit]

text: The AP Computer Science AB Examination was discontinued as of May 2009. The grade distributions from 2003 to 2009 are shown below:

text:
Score
2003[22]
2004[23]
2005[10]
2006[11]
2007[12]
2008[24]
2009[13]

5
37.6%
27.0%
31.2%
33.7%
33.2%
38.9%
39.3%

4
13.8%
18.5%
19.5%
19.7%
19.7%
19.1%
20.6%

3
24.6%
17.8%
18.5%
17.2%
18.3%
15.1%
16.1%

2
10.0%
12.0%
10.4%
9.3%
9.3%
9.0%
7.4%

1
13.8%
24.6%
20.4%
20.1%
19.5%
18.0%
16.5%

Mean
3.51
3.11
3.31
3.38
3.38
3.52
3.59

Students
7,071
6,077
5,097
4,939
5,064
4,995
3,881


document_title: Grandad (Only Fools and Horses)

question_text: what episode does grandpa die in only fools and horses

root

text: Grandad (Only Fools and Horses)

text: This article may need to be rewritten entirely to comply with Wikipedia's quality standards. You can help. The discussion page may contain suggestions. (October 2013)

tag: table

text:
Edward "Grandad" Trotter

Grandad (Pictured left)

Only Fools and Horses character

Portrayed by
Lennard Pearce (1981–1984)
Phil Daniels (2010–2011)

Duration
1981–1984 (OFAH)
2010–2011 (Rock & Chips)

First appearance
"Big Brother"

Last appearance
"Thicker than Water"

Created by
John Sullivan

Spin-off
appearances
Rock & Chips (2010–2011)

Classification
Former; regular

Profile

Occupation
Retired

[show]Family

Brothers
Albert Trotter
George Trotter
Jack Trotter

Sisters
Patsy Trotter

Wife
Violet Trotter

Sons
Reg Trotter

Grandsons
Derek Trotter
Rodney Trotter (step)

Nephews
Stanley Trotter
Kevin (in-law)

Nieces
Audrey Trotter
Gillian
Jean Trotter (in-law)

Other relatives
Damien Trotter (great grandson)
Joan Trotter II (step-great granddaughter)

text: Edward Kitchener "Ted" Trotter, better known simply as Grandad, was a character in the BBC sitcom Only Fools and Horses from 1981 to 1984. He was played by Lennard Pearce in the original series, and was portrayed by Phil Daniels in the prequel, Rock & Chips.[1]

tag: p

text: The character was grandfather to Del Boy, and Rodney Trotter, and older brother to Uncle Albert (Buster Merryfield). Lennard Pearce's death in December 1984 was written into the series with the death of the character.

text: Backstory[edit]

text: Born in Peckham Rye, London in 1909, Grandad stated that his earliest memories were of watching the soldiers marching off to World War I and witnessing their return after the armistice in 1918. He later spoke of the horror of these experiences with his description of the wartime government policy ("They promised us homes fit for heroes, we got heroes fit for homes!").

text: In 1924 after leaving school, Grandad got a job as a decorator working for the Council, but was sacked after just two days for wallpapering over a serving hatch. He then began working as a lamplighter for the London Gas Light and Coke Company, and trained as a chef at the Ear, Nose and Throat Hospital, but by the 1930s, he was unemployed and living with his parents and his brothers, George, Albert, and Jack, in Peabody Buildings, Peckham Rye. In 1936, he and his friend Nobby Clarke ran away to Tangier to join the French Foreign Legion, they were however unsuccessful and ended up working becoming gun runners during the Spanish Civil War. They were caught by the authorities. Nobby was tortured but Grandad chose to confess everything under interrogation. Both were deported from Spain and all her territories and dominions. He returned to Peckham and joined the dole queues, marrying his wife Violet sometime before the war, and fathering a son, Reg.

text: During World War II Grandad evidently served some time in the army as he told Del was given a double-headed coin by a fellow soldier and his son Reg checked his blood group on his old army records, however he must have been demobbed before the end of war as he temporarily separated from his wife and had an affair with Trigger's grandmother Alice, while her husband Arthur was still fighting. During the episode "He Ain't Heavy, He's My Uncle", Uncle Albert (Buster Merryfield) shows Del a photograph of Grandad during the war. When Del asks why Grandad is wearing a vest and plimsolls, Albert answers 'Well, he'd just deserted.'

text: After the war, Grandad had various short-term jobs before he retired, including working as a security officer at a warehouse in Chingford which he was sacked from after a janitor stole over three hundred briefcases from under his nose. His wife, who apparently worked as a char-lady in these later years died when Rodney was still young.

text: It is revealed in "Tea For Three", by Grandad's younger brother Uncle Albert (played by Buster Merryfield), that he and Albert fell out over Albert's later wife, Ada. Albert tells Rodney that while walking home from a nightclub together, they both had a fight, and never spoke to each other again after that.

text: In the programme[edit]

text: This article describes a work or element of fiction in a primarily in-universe style. Please help rewrite it to explain the fiction more clearly and provide non-fictional perspective. (February 2013) (Learn how and when to remove this template message)

text: This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (February 2013) (Learn how and when to remove this template message)

text: The character of Grandad was written out of the original show following the death of the actor Lennard Pearce but is featured heavily as a main character (called frequently by his real name "Ted") in the 2010-2011 prequel series Rock & Chips. Set in 1960, we see Grandad recently separated from his wife Vi, unemployed and subsequently homeless, after she finds out about his affair with Alice. Grandad then moves in with his son Reg. The Trotters are at that time squeezed into a two-up two-down terraced house and Grandad is forced to share a bedroom with his grandson Del. He appears to enjoy a close relationship with his family and remains with them when they move to their new council flat in Nelson Mandela House (which was then known as the "Sir Walter Raleigh House").

text: Grandad is seen in the first series of Only Fools and Horses. Grandad is by this point aged in his mid seventies, largely infirm and useless and still living at Nelson Mandela House with his grandsons. He is often seen watching two television sets at once, one black and white TV and one colour TV. In the Second Time Around it is revealed that he would normally watch three sets but one was being mended. Because of their sense of family loyalty, the Trotters ensure that he will always have a home, with Del dismissing his fiancée Pauline's suggestion of putting Grandad into a residential home because "he's family".[2] He is, however, often treated with a level of light-hearted abuse by Del and Rodney when his docile nature becomes an inconvenience causing desperation. For example, in "The Yellow Peril", Grandad takes a phone call for Del; Del informs him to tell whoever is on the other end that he has gone out. Grandad informs the caller of this, but then looks rather confused; he mutters "I'm not sure" before shouting "Where've you gone to, Del?"[citation needed] Grandad is a terrible cook; his miserably uttered final line in the series is "Del Boy, I've burnt yer pizza!" and in the first Christmas special even left the giblets in their plastic wrapping inside the turkey, not knowing what it meant by 'ready cleaned'. In the first episode when Rodney came home after a week’s absence he declined a meal cooked by grandad despite being ravenouy hungry. Del also played an April Fools joke on Grandad, telling him that the pools had called to say that he'd won half a million pounds. Grandad went to Soho and celebrated then realised that he didn't do the pools. Grandad's favourite television shows are Crossroads and The Dukes of Hazzard, as revealed in "Homesick" and "May The Force Be With You", and the former episode reveals that he also enjoys listening to The Archers on the radio. In "Yesterday Never Comes", Del suggests that he watches The Chinese Detective in his bedroom in order to remove him from the sitting room. Rather eccentrically, Grandad always watched two television sets at the same time. It was revealed that at one time he actually watched three television sets at a time before one broke down and was sent to be mended. He also owns an allotment, as mentioned in "The Russians Are Coming", as well as seen in "Mother Nature's Son". None of the main characters address Grandad by his name. Trigger addresses him as 'Mr Trotter' in Ashes to Ashes, and in "Who's a Pretty Boy?", even pet shop owner Louis greets him as 'Grandad'. His name is not revealed until Rock & Chips.

text: However, despite his senility and simplicity, Grandad was more crafty than he let on - wangling himself a bungalow by feigning illness being one of his many talents as seen in "Homesick". Similarly, in "Who's a Pretty Boy?", he conned Delboy out of £5, informing him the canary he purchased from the pet shop cost him £50, when in reality cost him £45 (Del Boy finds out at the end of the episode, and replied "£45?", to which Grandad innocently replies, "What did I say?") And in "A Slow Bus To Chingford" he almost succeeds in conning Del out of £50 by betting him that no-one will turn up for the Trotters' proposed 'ethnic bus tours of old London' - and then failing to deliver the tour's publicity leaflets (a ploy only foiled when Del discovers the discarded leaflets in the dust-chute at Nelson Mandela House). "It wasn't me, Del Boy," Grandad wails on being discovered on this occasion; "It was me brain!"

text: Grandad was also responsible for the spectacular (and noisy) failure of Del's chandelier cleaning business in "A Touch of Glass".

text: When Lennard Pearce died in 1984, writer John Sullivan chose not to replace him but to write the character's death into the series.[3] A funeral was held for Grandad in "Strained Relations", which saw the Trotter brothers trying to come to terms with the loss of a man who had been such an integral part of their lives. However, such was the nature of the show that amongst the sadness were moments of brilliant comedy. At the funeral, Del sees what he thinks is Grandad's trademark hat, takes it to the grave and he and Rodney lovingly drop the hat in. It is later revealed (to the audience) that the hat actually belonged to the Vicar. As Del and Rodney walk away from the grave, the gravediggers begin to fill in the grave; Del turns to them and menacingly says "Oi! Gently." This episode also introduced Grandad's younger brother Uncle Albert. It is also known that apart from Albert, Grandad had two more brothers: George, whom he mentioned in the episode "The Russians Are Coming"; and Jack, who was mentioned by Albert in "A Royal Flush", presumably the father of Del and Rodney's cousin Stan, who is seen at the funeral with his wife (Stan refers to George by his first name, making it improbable for Stan to be George's son).