OCR GCSE Computer Science Revision Flashcards - 2.1 to 2.5

Flashcards covering key concepts from OCR GCSE Computer Science Revision Guide (J277) Sections 2.1 Algorithms to 2.5 Programming Languages and Integrated Development Environments

A set of instructions, all placed in order, to complete a task.

What is an Algorithm?

Plain English, Pseudocode, Flow Diagram

Name three ways to represent an algorithm

Being able to think logically and critically when solving a problem. Being able to analytically solve a problem.

What is Computational Thinking?

Abstraction, Decomposition, Algorithmic Thinking

List the three thought processes of computational thinking

The process of removing any unnecessary elements to a problem, so you only focus on what is necessary and important.

What is Abstraction?

The process of breaking a large problem down into lots of smaller problems.

What is Decomposition?

The process of building a solution to solve a problem, where each of the stages/instructions are all in order.

What is Algorithmic Thinking?

Used to look for and find a specific piece of data within a data set (multiple pieces of data).

What is a Searching Algorithm?

Binary Search and Linear Search

What are the two searching algorithms?

A search algorithm that locates the midpoint within a data set, removing irrelevant halves until the piece of data is found. Requires the data set to be in order!

What is a Binary Search?

An algorithm that simply goes down the list checking each piece of data in turn until the data is found. The data set does not need to be in order!

What is a Linear Search?

Better for searching through large data sets as it is quicker in locating data.

When is Binary Search Better?

Can be used on any list, whether it is sorted or unsorted and Better for searching through small data sets

When is Linear Search Better?

Used to rearrange/reorder the data within a data set into a specific order (e.g. smallest to largest, alphabetical order etc.)

What is a Sorting Algorithm?

Bubble Sort, Merge Sort, Insertion Sort

What are the three sorting algorithms?

Looks at two pieces of data in turn, rearranging them if needed before moving onto the next two pieces of data. The process is called a pass and is repeated until no pieces of data are moved.

What is a Bubble Sort?

Breaks the data set up into pairs, rearranges those pairs, begins merging those pairs together, and repeats the process until the whole data set is merged back together and rearranged.

What is a Merge Sort?

Creates a temporary list, works through the data set, and places each piece of data into the correct location in the temporary list.

What is an Insertion Sort?

variablename = 3

State the pseudocode command to store an integer variable

variablename = 'string'

State the pseudocode command to store a string variable

CONST variablename = 3

State the pseudocode command to create a constant

str(20)

State the pseudocode command to cast an integer to a string

int(“20”)

State the pseudocode command to cast a string to an integer

variablename = input()

State the pseudocode command to get input from the user

print(“Hello”)

State the pseudocode command to output a string

print(5)

State the pseudocode command to output an integer

if … then, elseif … then, else, endif

State the pseudocode command used to create selection?

while …, endwhile

State the pseudocode commands used to create a while loop

for …, endfor

State the pseudocode commands used to create a for loop

Terminal, Process, Decision, Input/Output, Sub-Routine, Arrow

What shapes are associated with creating a flowchart?

Oval shape, used to start and end the flowchart

What is the Terminal shape and its function?

Rectangle shape, used to show a process (something being calculated)

What is the Process shape and its function?

Diamond shape, used to represent a decision (yes or no)

What is the Decision shape and its function?

Parallelogram shape, used to represent input and output of data

What is the Input/Output shape and its function?

Rectangle with lines down each side, used to represent the call to a sub-routine

What is the Sub-Routine shape and its function?

Used to simulate the execution of an algorithm and looking for any logic errors that may be hiding in the algorithm which is an error that causes the program to work incorrectly.

What is a Trace Table?

Used to store a single piece of data, but the contents can be changed.

What is a Variable?

Used to store a single piece of data, but the data does not change within the program (it remains constant/the same).

What is a Constant?

Used to represent an action e.g. + which represents addition

What is an Operator?

Data which is entered into the computer program

What does Input refer to?

Data which is sent out by the computer program

What does Output refer to?

This is when a value is set/given to a variable

What does Assignment refer to?

A basic programming construct, this is when the code/instructions are all in order, so that one piece of code executes, followed by the next etc.

Expand on Sequence

A basic programming construct, this is when a choice/decision is used within a program, allowing for multiple outcomes dependent on the data that is inputted

Expand on Selection

A basic programming construct, this is when a section of code is repeated.

Expand on Iteration

A type of iteration, where the code is repeated until a certain condition is met. This means the code could execute any number of times, as it relies on the condition being met before stopping.

Expand on Condition Controlled Iteration

A type of iteration, where the code is repeated a specific number of times. This means the code will only execute this number of times before stopping.

Expand on Count Controlled Iteration

A data type which is used when storing alphanumeric characters and symbols.

What is a String?

Refers to when a string is altered or edited to suit the means of the program.

What does String Manipulation refer to?

Refers to when strings are brought together and combined

What does String Concatenation refer to?

Refers to when a string is split at specific points, separating the single string into multiple strings

What does String Splitting refer to?

Used to store data beyond whilst the program is running

What is a Text File?

Used to store large amounts of data beyond whilst the program is running. Offers a more secure way of storing data

What is a Database?

Refers to all data stored about a single data subject within a table and is often seen as a single row within a table.

What does Record refer to in databases?

Refers to the various categories for which data is collected and is often seen as a single column within a table.

What does Field refer to in databases?

The language used to manage, maintain, and query a database.

What is SQL?

Used to determine which fields will be extracted

What does SELECT do in an SQL query?

Used to determine which table the data will be extracted from

What does FROM do in an SQL query?

Used to set the criteria for the query, but is not necessarily needed.

What does WHERE do in an SQL query?

Allows you to store multiple pieces of data in the same location

What is a List?

Stores one piece of data per data subject, identified using a single index

What is a One Dimensional List?

Stores multiple pieces of data per data subject, identified using two indices

What is a Two Dimensional List?

A section of code that is ‘called upon’ within a program when being executed, allowing for the same piece of code to be used without having to repeatedly write it out

What is a Sub-Program?

Data that is passed into a sub-program to be used within the sub-program

What is an Argument?

The variables that are passed into a sub-program to be used within the sub-program

What is a Parameter?

A type of sub-program which is a sequence of instructions which returns a value

What is a Function?

A type of sub-program which is a sequence of instructions which do not return a value

What is a Procedure?

Refers to the way data is stored within a program and determines what type of operations can take place on the data.

What is Data Type?

A data type, used to store whole numbers

What is an Integer?

A data type, used to store a TRUE/FALSE value A data type, used to store numbers that require decimal places

What is a Boolean?

A data type, used to store numbers that require decimal places

What is Real/Float?

A data type, used to store a single character

What is a Character?

Refers to the process of altering a variables data type within a program

What is Casting?

Refers to the various operators used to perform arithmetic calculations within a program (+, -, *, /)

What is an Arithmetic Operator?

Is short for Quotient, and is used to find the whole number of a division

What does DIV mean?

Is short for Modulus, and is used to find the remainder of a division

What does MOD mean?

Refers to the various operators used to perform comparisons on data within a program which provides more focused results (AND, OR, NOT)

What is a Boolean Operator?

A function built into python which allows for random choices to be made, used during random number generation

Expand on Random

The process of ‘cleaning up’ a user’s input so it is in a suitable format ready for processing

What is Input Sanitisation?

The process of checking the user has inputted data in the correct format

What is Validation?

The process of having a ‘back up plan’ in case the original plan fails

What is Contingency Planning?

When a user does not use the program the way it was designed to be used

What does Misuse refer to?

The process of ensuring a user has the rights/permissions to access a program

What is Authentication?

This refers to ensuring the program can be easily updated, improved, and fixed

What does Maintainability refer to?

Used within a program to help briefly identify what a section of code does

What are Comments?

A ‘rule of thumb’ programmers will use when writing in a specific language, following certain rules when naming identifiers such as use of lowercase/uppercase characters, underscores etc.

What are Naming Conventions?

The process of assessing whether a program works correctly and the way it should work, aiming to find ‘bugs’ and rectify them so the program is faultless

What is Testing?

A type of testing that is carried out throughout the development of the program in multiple ‘mini tests’ on sections of code

What is Iterative Testing?

A type of testing takes place once the program has been completed and tests the whole program at the end of its development

What is Final/Terminal Testing?

An error within the code, meaning the code has been incorrectly written and will stop the program from working

What is a Syntax Error?

An error that does not stop the program from working, but stops the program from working the way it should do

What is a Logic Error?

The data that is selected to be used when testing a program What is Normal Data? A type of test data, this data is correct and should be accepted by the program

What is Test Data?

A type of test data, this data is of the correct data type but outside of the requirements set

What is Invalid Data?

A type of test data, this is data that is on the edge of a range specified by the program and therefore should be accepted

What is Boundary Data?

A type of test data, this is data that is of the incorrect data type and therefore should be rejected

What is Erroneous Data?

This is the language of the computer. Binary is used to represent all data within a computer system using 1/0.

What is Binary?

A way we can represent Boolean operations consisting of AND, OR, and NOT

What is Logic Diagram/Gate?

A type of logic gate in which both inputs must be TRUE (ON or 1) for the output to be TRUE (ON or 1)

Expand on the AND Gate

A type of logic gate in which one or both inputs must be TRUE (ON or 1) for the output to be TRUE (ON or 1)

Expand on the OR Gate

A type of logic gate that the output is the opposite of the input

Expand on the NOT Gate