EOM Revision

EOM Revision

1. Robust programs

   • Data Sanitisation
     • Switching 3 for E for example
   • Data Validation
     • Checks the input field to make sure everything inputted is acceptable and permitted.
     • Range, Input, Length, Format, presence, spell check. lookup table, Check digit.
     • Checks the input field to make sure everything inputted is acceptable and permitted.
   • Producing a robust program
     • Testing
       • Iterative testing
         • Testing as you go along.
       • Final testing
         • Testing at the end of the code
     • Comments,
       • Using comments will help you remember what each line does.
     • Test Data
       • Valid data
         • Data that is valid and should work.
       • Extreme data
         • Extreme data is test data close to or from the expectations that should be accepted by the system.
       • Invalid Data
         • Data that shouldn't work
       • Null Data
         • Basically no data, valued at 0 or nothing.
       • Erroneous data
         • Incorrect data
     • Indentation
       • Indentation is a way of identifying functions easier and reading code better
     • Identifiers
       • For example using UserName instead of XFYTT.

2. Algorithms

   • Sorts
     • Merge sort
       • Split list into individual lists, then combines them in 2 each time
     • Bubble sort
       • Moving through list repeatedly, swapping elements that are in the wrong order
   • Search
     • Binary
       • An ordered list is divided in 2 with each comparison
     • Linear
       • Each item is searched in order
   • Key words
     • Abstraction
       • Simplifies problem by removing unnecessary detail
     • Decomposition
       • Breaking down problem into smaller parts

3. Data representation

   • Bits and bytes
     • Smallest unit of data is a bit. It can either be a1 or a 0
     • 1024 bytes is 1 KB. 1024 KB is 1 MB. 1024 MB is 1 GB.
     • Binary
       • 1s and 0s
   • Hex
     • Hexadecimal is way of representing binary numbers, so you can write them quicker.
     • Hex can store up to 16 bits.

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