Intro

This is definitions of Computer Science related page

Numbers

The numbers in CS can be

  1. Binary 0, 1
  2. Octal 0, 1, 2, 3, 4, 5, 6, 7
  3. Decimal 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
  4. Hexadecimal 0, 1, 2, 3, 4, 5, 6, 7, 8, a, b, c, d, e, f

Example

take 25 as example

>>> number = 25 
>>> number #Decimal
25
>>> bin(number) #Binary
'0b11001'
>>> oct(number) #Octal
'0o31'
>>> hex(number) #Hexadecimal
'0x19'

The notation of this tutorial will always be:

  • Binary -> 0b
  • Octal -> 0o
  • Decimal -> NA (No Notation)
  • Hexadecimal -> 0x

That is 0b11001 = 0o31 = 0x19 = 25

Least Significant Bit (LSB)

the bit of the data, which is also the low-order bit or right-most bit

Example

>>> def LSB(n):
...     return n&1
>>> number = 15
>>> bin(number)
'0b1111'
>>> LSB(number)
1
>>> number = 14
>>> bin(number)
'0b1110'
>>> LSB(number)
0

Most Significant Bit (MSB)

The high-order bit or left-most bit

Example

Given a 8 bit system

>>> def MSB(n):
...     return n >> 7
... 
>>> number = 215
>>> bin(number)
'0b11010111'
>>> MSB(number)
1
>>> number = 127
>>> bin(number)
'0b1111111' #It's actuall 0b01111111 since it's a 8-bit system
>>> MSB(number)
0