2.1 Algorithms

Question 1

Define Abstraction

Answer 1

Including only the necessary details and leaving out the unnecessary details when problem solving

Question 2

Define Algorithmic thinking

Answer 2

A way of getting to a solution by identifying the steps needed

Question 3

Define Decomposition

Answer 3

Breaking a problem down into smaller sub-problems, making the overall problem easier to solve

Question 4

Define Algorithm

Answer 4

A sequence of steps designed to perform a particular task

Question 5

Define Flowchart

Answer 5

A method of designing algorithms before coding using symbols

Question 6

Define Pseudocode

Answer 6

1) Language independent description of the steps of an algorithm.
2) Has no defined syntax, so it cannot be compiled or interpreted by the computer.

Question 7

Define Binary search

Answer 7

1) Accessing the middle record and determining whether the data item has been found.
If not, checking whether it is before or after the current record in the data set.
2) Discarding the half of the data set that does not contain the record in each pass.
3) Repeating the algorithm until the data item is found or it is not in the data set.
It only works if records in the file are in sequence

Question 8

Define Bubble sort

Answer 8

1) Repeatedly steps through a data set comparing each pair of adjacent items
2) Swaps pairs of items if they are in the wrong order
3) Stops when no swaps are made

Question 9

Define Insertion sort

Answer 9

Finds the correct location in a list for an item…
…By comparing it to the other items in the list in a linear way…
…Inserting the new item at the correct position…
…By moving all the other items after it by one index

Question 10

Define Linear search

Answer 10

Examining each data item in turn until the item is found or the end of the data structure / file is reached

Question 11

Define Merge sort

Answer 11

1) A divide and conquer algorithm
2) A list is repeatedly divided into smaller lists eventually containing just one item.
3) Each element is compared with the adjacent list…
…And merged back together from two lists into one

Question 12

Define Syntax errors

Answer 12

Errors that break the grammatical rules of the programming language and prevent it from being run or translated

Question 13

Define Logic errors

Answer 13

Errors that produce unexpected output/incorrect results but won’t stop the program from running