unit 6- algorithms

Question 1

A computer game is written in a high-level programming language.
(a) State why the computer needs to translate the code before it is executed

Answer 1

interpreter translates code into machine code, instruction by instruction - the CPU executes each instruction before the interpreter moves on to translate the next instruction. Interpreted code will show an error as soon as it hits a problem, so it is easier to debug than compiled code.

Question 2

Describe the difference between how a compiler and an interpreter would translate the
code.

Answer 2

Interpreter translates just one statement of the program at a time into machine code. Compiler scans the entire program and translates the whole of it into machine code at once

Question 3

what is a constant in programming

Answer 3

Data values that stay the same every time a program is executed are known as constants

Question 4

what is a binary search ?

Answer 4

It works by repeatedly dividing in half the portion of the list that could contain the item, until you’ve narrowed down the possible locations to just one.

Question 5

how does a linear search work

Answer 5

Starting at the beginning of the data set, each item of data is examined until a match is made. Once the item is found, the search ends.

Question 6

what is a bubble sort ?

Answer 6

each item is compared with the one on the right and swapped if larger. at the end of the first pass the largest item is last.

an example: ( 15 , 9,7, 6 )
the first pass (9,7,6,15)
the second pass ( 7,6,9,15)
the third pass ( 6,7,9,15)

Question 7

what is an insertion sort ?

Answer 7

the algorithm sorts one data at a time.

its similar to how you wold sort a deck of cards

Question 8

here is a list 9,5,4,15

use and describe the method of an insertion sort

Answer 8

first you compare 9 and 5 9 is bigger so you swap them
list is now 5,9,4,15
you now compare 4 to the first two sets of data its the smallest so therefor goes first.
list is now 4,5,9,15

you then compare 15 but 15 is the highest so stays at the back

Question 9

here is a list 9,5,4,15

use the bubble sort to sort the list

Answer 9

first pass (5,4,9,15) 
second pass (4,5,9,15)

Question 10

What is the method of a merge sort ?

Answer 10

Divide the unsorted list in two
Continue to divide these lists into two until there is just one item in each list
Now merge each list back until there is only one list remaining – which will be the fully sorted list

Question 11

What are the method of a merge sort ?

Question 12

Pros and cons of linear search

Answer 12

Easier to understand than binary and works on any list

Can be inefficent when looking at longer lists

Question 13

Pros and cons of binary search

Answer 13

More efficent with longer lists

Harder to understand and only works on sorted lists

Question 14

Pros and cons of a merge sort ?

Answer 14

More efficent than bubble and instertion with longer lists

Uses more memory

Question 15

Pros and cons of bubble

Answer 15

Easier to understand

Inefficent in longer litsts

Question 16

Pros and cons of insertion sort

Answer 16

Easy to understand

Time consuming and ineffective with longer lists

Question 17

What is decomposition

Answer 17

Breaking a large problem into smaller more manageable ones

Question 18

What is abstaction

Answer 18

Removing the unnecessary detail from a problem to leave only the important parts