1.4 - Data types, Data Structures and Algorithms (Unfinished) Flashcards
Worded Effect of Bitwise Mask: AND
- EXTRACTS a subset of the bits in the value; when the mask is 1, you are copying the original binary sequence and when the mask is 0, you are blanking it.
Worded Effect of Bitwise Mask: OR
- Can SET a subset of the bits in the value; when the mask is 1, sets value to 1 and when the mask is 0, you are leaving it alone.
Worded Effect of Bitwise Mask: XOR
- TOGGLES a subset of the bits in the value: when the mask is 1, the value is changed (“toggled”) and when the mask is 0, the value stays the same
Output of values in instances of Bitwise Mask: AND
- If both values are 1: Output = 1
- If not: Output = 0
Output of values in instances of Bitwise Mask: OR
- If either the value or the mask is 1: Output = 1
- If both are 0: Output = 0
Output of values in instances of Bitwise Mask: XOR
- If the value and the mask are different (one is 0 and the other is 1): Output is 1
- If the value and the mask are the same (both 0 or both 1): Output is 0
What is a Character Set?
- The characters or symbols that can be recognised, represented, interpreted, understood and used by a computer.
- Each required character is represented by a unique binary code or number so each symbol is distinguishable from
all others.
Similarities between ASCII and Unicode
- Both use binary to represent characters / are character sets
- The first 7/8 bits of Unicode is the same as ASCII (overlaps)
Differences between ASCII and Unicode
- ASCII has fewer characters (128/256); Unicode has more characters
- ASCII is 7/8 bits whereas Unicode can be larger (16/32 bits) and can have variable sized characters
- ASCII limited to Latin / English / European characters whereas Unicode can represent other symbols (e.g. Chinese/Emojis)
What does ASCII stand for?
American Standard Code for Information Interchange
Describe an Array
A static data structure that holds multiple pieces of data (of the same data type) contiguously in memory with a single identifier
Dimensions of Arrays
- 1D Array - A single set of data, which can be visualised in a single row
- 2D Array - A set of data that can visualised in rows and columns; items are called by [Row Num. , Column Num.]
- 3D Array - A collection of 2D Arrays that can be visualised one behind the other; items are called by [2D Array Num. , Row Num. , Column Num.]
Describe a Record
- Can store multiple values under one identifier
- The data can be of different data types
Describe a List
- A mutable collection of items that can store more than one data type
- Size is not fixed and items can be changed or replaced
- [] in Python
Describe a Tuple
- An immutable collection of items that can store more than one data type
- Size is fixed and items cannot be changed or replaced
- () in Python
Static vs.Dynamic
- Static - A data structure whose size cannot be changed at runtime
- Dynamic - A data structure whose size can be changed at runtime
Mutable vs. Immutable
- Mutable - Its structure and the data it contains can be changed at runtime
- Immutable - Its structure and the data it contains cannot be changed at runtime
Describe a Linked List
A dynamic data structure where each node consists of data and a pointer that gives location of next node
Describe a Graph
- A collection of data nodes with connections () set between them
- Graphs (edges) can be directed (directional or bi-directional) or can undirected
- Graphs can also be weighted to show relationships between nodes such as distance
Describe a Stack
- A dynamic Last In First Out (LIFO) data structure; data is added to (Pushed) and removed (Popped) from the top of the stack
- There are 2 pointers: a top (often called ‘Stack Pointer’) and a bottom
Describe a Queue
- A linear and dynamic First in First Out (FIFO) data structure; data is removed (dequeued) from the front of the queue and added (enqueued) to the back of the queue
- There are 2 pointers: a top and a bottom
Describe a Tree
- A non linear and dynamic branching data structure that consists of a Root Node and sub nodes that are connected by edges
- Trees are 1 directional and unweighted
Describe a Binary Search Tree
- A specific kind of tree where each node can only have a maximum of 2 children nodes
