### Algorithm and Pseudocode

Algorithm
is simply put, a well defined computational procedure consisting of

**, that take some value or set of values, as**__a set of instructions__**, and produces some value or set of values, as**__input__**An algorithm is usually presented in the form of some**__output.__**, which is a mixture of**__pseudo-code__**English statement**, some mathematical notations and selected keywords from a programming language.
Here’s how it works: INPUT, PROCESS
(calculations, decisions and so on) and OUTPUT

Human example: You hear a question via your
ears (input). You need to find an answer and you think (process). You then give
the answer by speech (output).

Similarly,
in a computer system, your keyboard or mouse is an input because you supply or
give information to the computer. The CPU decides what to do with the
information, which is called process. After calculation, it shows the result on
the screen, which is called output.

Let us do a
simple example.

You want
the computer to add 2 numbers and give you the result (sum).

**5+4**

The numbers
5 and 4 are called value1 and value2 respectively.

To get the
sum the computer would need to add these 2 values. Hence:

**sum=**

**value1 + value2**

5 + 4

= 9

In computer
studies, we use mathematical symbols to do calculation just like in a normal
mathematics class. The only difference is that the multiply symbol changes from

**X**to*****. This is to avoid confusion. Also, the divider symbol changes to just a forward slash**/.**
The list of
symbols:

+ addition

- subtraction

* multiplication

/ division

= assignment

( ) brackets for
grouping calculations

Here is how
an algorithm will look using pseudocode:

*Read value1, value2*

*SUM=value1 + value2*

*DISPLAY SUM*

**Pseudocode Language**

Pseudocode
does not require that you write a complete sentence. For instance someone asks
if you’re a boy or female a complete answer would be “I am a girl”. But you
could answer rapidly by only answering “girl”. Saves lots of time and tying!

Example:
You are a teacher who created a program to see if a student has passed. Let us
make as if the computer was a human. You would talk to him like this: “If the
student has 50 points exactly or more than 50 then he has passed.” Remember:
Read between lines. What to do if the student hasn’t got 50 or more points? It
means that he has failed! You must think about the “

**WHAT IF THIS HAPPENS**?”
Let us put
this in pseudocode: Remember! We need not write complete sentences.

>=

*this symbol means ‘greater or equal to’***Read**mark

**If**mark >= 50

**Then**

STUDENT PASS

**ELSE**

STUDENT
FAIL

**END IF**

Let me
explain the if, else, end if.

We use

**If**when we need to compare. Here, we are comparing numbers. Hence it means**‘if the mark is greater or equal to 50’.**
We use

**Then**to tell the computer what to do if the mark is really equal to or greater than 50.
We use

**ELSE**to tell the computer what to do if the mark if lower than 50.
We use

**END IF**in all psuedocode. It simply tells the computer that it needs to stop calculating or processing.
Example:
You are looking for a pair of shoes not exceeding $50. In this example we use
the

**<=**(is less than or equal to).**Read**price

**If**price <= 50

**Then**

BUY

**ELSE**

DON’T
BUY

**END IF**

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