1.4.2: data structures

• What is an array

  An ordered, finite set of elements of a single type
• What type of array is a linear array?

  A one dimensional array.
• How can you visualise a two dimensional array?

  You can visualise it as a spreadsheet/table.
• How can you visualise a three dimensional array?

  A three dimensional array can be visualised as a multi-page spreadsheet
• What is a record also known as?

  A row in a file
• What is a record made up of?


  A record is made up of fields
• How can you identify a field from a record using programming?

  recordName.fieldName
• What is the definition of a list?

  A data structure consisting of a number of items, where the items can occur more than once.
• What are the main differences between arrays and lists?

  • Lists can store data non-contiguously whereas arrays store data in order.
  • Lists can store data of more than one data type.
• What is a tuple?


  An immutable, ordered set of values of any type.
• What is the difference between a tuple and an array?

  Tuples are initialised using regular brackets instead of square brackets.
• What is a stack?

  A last in first out data structure, where items can only be removed from and added to the top of the list
• Give an example of where stacks may be used

  • Back button in a web page
  • Undo buttons
• What is a queue

  A first in first out data structure, where items are added to the end of the queue and removed from the front of the queue.
• What does the operation isEmpty() do?

  Checks to see if the stack is empty
• What does the operation push(value) do?

  Adds a new value to the top of the stack
• What does the operation peek() do


  Returns the top value of the stack without removing it
• What does the operation pop() do?

  Returns and removes the value at the top of the stack
• What does the operation size() do?

  It returns the size of the stack
• What does the operation isFull() do?


  Checks to see if the stack is full
• What does the operation enQueue(value) do?

  Adds the value to the end of the queue
• What does the operation deQueue() do?

  Removes the item from the end of the queue
• What does the operation isEmpty() do?


  It checks to see if the queue is empty
• What does the operation isFull() do?

  Checks to see if the queue is full