3.2 Writing and Following algorithms

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

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

• 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

Halfway house between english statements and a program code

Swaps items in different passes

Must be sorted (divide and conquer)

Comments to document

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

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

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

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

Encrypts client to user data connections