Algorithms - What are they? , how do you write them?

Página 1

What are algorithms?

Algorithms are representations of how to solve problems. These problems can be in code or in everyday life. For instance you could write an algorithm on how to brush your teeth. In fact you probably, without even knowing it, mentally write hundreds of algorithms every day.

How can algorithms be written?

Algorithms can be written as both flowcharts and pseudocode.

Flowcharts

Flowcharts are diagrammatic representations of steps taken to solve a problem. They use various shapes to represent different things.

The shapes are:

Rhombus = decision

Parallelogram = Output or input (information going out or in)

Rectangle = Process (somthing being done)

Rectangular circle = Start / stop

Lines with arrows indicate the direction of flow (in which order things are done).

This is an example of a flowchart

Página 2

What is pseudocode?

Pseudocode is a written representation of an algorithm using various code like terms but remember pseudocode is not actual code. These are the pseudocode terms:

OUPUT: showing something on the screen or electronic device - usually requiring an input afterwards

INPUT: something that the user puts into the program

STORE: a process that stores data in the program

IF: represents a condition e.g if colour = red

THEN: Showing what to do if the condition is true

ELSE: showing what to do if the condition is false

Here is an example

OUPUT: "How are you?"

INPUT: User inputs how they are

STORE: Store users input in answer variable

IF: answer = fine THEN OUTPUT: "That's good"

ELSE

OUPUT: "You need to go to a doctor"