Data Representation

In this post I will be going over how different types of data can be represented.

Positive numbers- these are represented by using two numbers 0 and 1. 0 represents 0 and 1 is on. This is called the binary system. Using 1 byte the  lowest number that can be represented is 0 and the biggest number than can be represented is 255. It starts at 1 and to get the next value 1+1= 2, and then do the same, 2+2=4 etc. Eventually it will look like this

128      64            32            16            8            4            2            1

I will explain how convert decimal numbers to binary. If the number is 82 then the following process would be carried out:

Does 128 go into 82? No

128

0

Does 64 go into 82? Yes

64

1

Subtract 64 from 82

= 18

Does 32 go into 18? No

32

0

Does 16 go into 18? Yes

16

1

Subtract 16 from 18

=2

Does 8 go into 2? No

8

0

Does 4 go into 1? No

4

0

Does 2 go into 2? Yes

2

1

Subtract 2 from 2

=0

Does 0 go into 1?

No

This brings

128      64            32            16            8            4            2            1

0          1            0            1            0            0            1            0

Negative numbers- the simplest way of understanding this is by using signed bits. This means  the user uses the first number to represent whether the number is positive or negative. This is an example:

011=3

111=-3

Real Numbers- These are represented by using floating point represented.

The mantisa – the number without the point

The exponent – the number of places the point must be moved to its original position

Text – this includes ASC11. This code is used all around the world convert English language to American.

Bitmapped Graphics

Pixels- an image made up of tiny dots

Resolution – this less pixels there are the blurrier the picture.  Vice-versa the quality is better.

 

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One Response to Data Representation

  1. Great post Ryan, really detailed. The one thing you missed out was 2s complement for storing -ve numbers.

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