3.2 Writing and Following algorithms

Question 1

Algorithm

Answer 1

An algorithm is a set of instructions so solve a problem or complete some well-defined task in a finite number of steps

Question 2

Different types of problems solve by algorithms

Answer 2

• Routing
• Timetabling
• Searching
• Encrypting
• Sorting
• Writing a compiler

Question 3

Features of good algorithms

Answer 3

• Has clear and precisely stated steps that produce the correct output for any set of valid inputs
• Should allow for invalid inputs
• Must always terminate at some point
• Should perform the task efficiently, in as few steps as possible
• Should be designed in such a way that other people will be able to understand it and modify if it necessary

Question 4

Pseudocode

Answer 4

Halfway house between english statements and a program code

Question 5

Bubble sort

Answer 5

Swaps items in different passes

Question 6

Binary search

Answer 6

Must be sorted (divide and conquer)

Question 7

Features of a good program

Answer 7

Comments to document

Question 8

What are some good ways to follow an algorithm?

Answer 8

Create a trace table with columns for each variable in the order in which they appear in the program and a column for the output, follow through the algorithm line by line and fill in the value of a variable whenever it changes

Question 9

Internet related algorithms

Answer 9

Algorithms that are used to manage and manipulate huge amounts of data stored on the internet

Question 10

Route-finding algorithms

Answer 10

Used to determine the best possible route to transmit packets of data from point A to point B over a network

Question 11

Compression algorithms

Answer 11

Used to compress data files so that they can be transmitted faster or held in a smaller amount of storage space

Question 12

Encryption algorithms

Answer 12

Encrypts client to user data connections