2.1 Algorithms

• Abstraction


  Obscuring unnecessary detail so that main processes can be more easily understood, by creating a representation of something.
• Decomposition


  Used to break down a complex problem into small parts that are easier to solve.
• Algorithmic thinking


  Producing a series of steps a program has to perform in order to solve a problem.
• Binary search


  Repeatedly dividing in half the portion of the data list that could contain the required item. Only works if list is sorted. More efficient than linear search.
• Linear search


  Compares each value in turn.
• Bubble sort


  Repeatedly go through list to be sorted. Compare each pair of items next to each other, swap if required.
• Insertion sort


  Create 2 lists. Name one sorted and the other unsorted. Take next element from unsorted list and insert into correct position in sorted list. Repeat until all items are in correct position.
• Merge sort


  List split into individual elements.
• Characteristics of Bubble sort


  Benefit: Simple to implement.

  Drawback: Inefficient for large lists.
• Characteristics of Merge sort


  Benefit: Faster than Bubble and Insertion.

  Drawback: More difficult to code than Bubble and Insertion.
• Line


  An arrow represents control passing between the connected shapes.
• Process


  This shape represents something being performed or done.
• Sub Routine


  This shape represents a subroutine call that will relate to a seperate, non-linked flow chart.
• Input/Output


  This shape represents the input or output of something into or out of the flow chart.
• Decision


  This shape represents a decision(Yes/No or True/False) that results in two lines representing the different possible outcomes.
• Terminal


  This shape represents the "Start" and "End" of the process.