Computer Science Edexcel GCSE Exam Questions With Verified Correct Answers Graded A++
What is a data structure?
An organised collection of related elements
What is an array?
an object used to store multiple values of the same data type in a single variable.
What is a record?
A data strutc...
What is a data structure?
An organised collection of related elements
What is an array?
an object used to store multiple values of the same data type in a single variable.
What is a record?
A data strutcure that stores a set of related elements of different data types. Each
element in a record is known as a field.
What is a field?
An element in a record.
REMINDER
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What is decomposition?
The process of breaking down a complex problem into smaller parts, implemented by
coding subprograms, making it easier to solve.
What is abstraction?
Picking out the important bits of information from the problem, ignoring the specific
details that don't matter.
What is a procedure?
A subprogram that does not return a value
What is a function?
A subprogram that returns a value
What is a local variable?
A variable that only exists within the subprogram.
What is a global variable?
A variable stored in the main program and can be used anywhere.
,What is a parameter?
A way that programmers pass input values into subprograms by making each
subprogram a general solution to a task.
What is an algorithm>
a set of well-defined steps for performing a task or solving a problem
What is a dry run?
A method used to investigate the functioning of an algorithm, by executing the program.
What is a logic error?
when compiler or interpreter is able to run program but program does something
unexpected
What is a 2d list?
A 2D list is a list of separate lists. e.g lst = [[1,2,3] , [2,3,4]]
What are different ways to validate an input? (5)
• Range check - to ensure that the date entered falls within specified boundaries
• Length Check - to ensure the length of value enters within a specified range
• Presence check - simply ensures that a value has been presented to the program,
preventing the the use from leaving an input blank.
• Look-up check - Ensuring that a value is one of a pre-defined set of acceptable values
(which are stored in a 1D list)
• Menus - to ensure that the option selected is permissible and part of the program
menu.
What is authentication?
Authentication is used to ensure that a person attempting to log into a computer system
or device is permitted to have access.
What is a bubble sort?
Different items must be compared with each other and moved so that they are in either
ascending order or descending order. The algorithm starts at one end of the list and
compares pairs of data items. If they are in the wrong order they're swapped. Each
complete traversal of the list is called a pass. The process is repeated until there have
been no swaps during a pass.
What is a merge sort?
, It divides the list into two parts. It repeats this until the size of each list contains one
item. It then repeatedly merges each pair of lists with the times in the correct order.
What does it mean when an algorithm uses brute force?
It starts at the beginning and completes the same task over and over again until it has
found a solution.
What does it mean when a sort method is an in-place sort?
It does not need to make copies of the arrary or large parts of it.
What does divide and conquer mean for algorithms?
It repeatedly breaks down the problem into smaller sub-problems, solves those and
then combines the solutions.
What is a linear search?
A brute force algorithm that looks at the beginning of the array and goes through it, item
by item, until it finds the date it is looking for or reaches the end of the array without
finding it and stops.
What is a binary search?
A "divide and conquer" search of which is used to find a value in a sorted list where you
check the middle first, then cut the list in half depending on the value of the item. You
repeat the process until you find the value.
what is a binary search?
An algorithm to find a value in a sorted list where you check the middle first, then cut the
list in half depending on the value of the item. You repeat the process until you find the
value.
What is binary?
A system of numbers using only two digits 0 and 1, as transistors have only two discrete
states, on and off
What is a bit?
A binary digit - 0 or 1.
How do you calculate the number of binary patterns that can be produced by a
group of n bits?
2^n
What is a byte?
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