Abstraction and Automation

Abstraction and Automation

1. Algorithms

   • 'Algorithm' comes from the name of a Latin book called 'Algoritmi de numero Indorum'
     • This means 'Al-Khwarismi on the Hindu Art of Reckoning'
   • The aim of algorithms is to be as specific as possible
     • Ambiguity can lead to issues
   • Must be in a defined sequence as order is important
   • Use four basic structures
     • Sequence
     • Selection
     • Iteration
     • Assignment
   • Must terminate
   • The AQA definition is 'a sequence of steps that can be followed to complete a task and that always terminates'

2. AQA's preferred pseudo-code conventions

   • Sequence
     • INPUT, OUTPUT, etc.
   • Assignments
     • x <--- 10
   • Selection
     • IF, THEN, ELSE, ENDIF
   • Iteration
     • FOR, ENDFOR, WHILE, ENDWHILE, REPEAT, UNTIL

3. Trace tables

   • Why use them?
     • Makes sure an algorithm will work properly
     • A dry run of a program will help troubleshoot
   • Tracks the values of variables throughout the program