Software Comp 4.1 - 4.2

Software Comp 4.1 - 4.2

1. High

   • Easier than machine code, still hard though
     • Python, Greenfoot, Scratch
   • made for us read and write easier
     • Computers cannot run high level code tho
       • to be able to run it, you gotta put it in a compiler or interpreter (these are translators)

2. Low

   • Executed Directly by computer
   • hard to read and write
   • Two types
     • Machine
       • Written in binary
       • 1s and 0s fetched and executed by CPU
       • Binary value that represents an instruction (called an opcode)
       • Data in binary form (called and operand)
     • Assembly
       • written in words
         • Represents each binary command
         • uses MNEMONICS instead of binary
           • Load 5, Add 4, Store 2
         • Little Man is an assembly emulator

3. Compiler

   • what id do
     • takes code and translates in one go
     • makes a new file with only machine code and finesses the high level
     • can be used by computer now
   • advantages
     • speed
       • faster as translation has been done already
     • security
       • can distribute exe files without source code
         • hard to trace back
   • speed is important
     • in stuff like games, software, utilities

4. interpreter

   • what id do
     • this one don't make a new file
     • used to execute original code directly
     • translates line by line unlike the other one
     • python and scratch are interpreted languages
   • advantages
     • compatability
       • will run on any computer
     • debuggin
       • fix error easier
         • can identify line with error
   • compatibility is important
     • javascript + other web-based code

5. Errors

   • Syntax
     • non-valid code
       • print ("hello) - missing quote
   • Run-time
     • Impossible operation
       • 0 / 0
   • Logical
     • Program executes and exits with no errors but what is expected did not happen
       • hard to detect and fix as no error is prdouced
       • Prime checker say 20 is prime
   • Linking
     • When a program tries to import function from non existing file
   • Rounding
     • Occurs when a value is rounded and loses accuracy
   • Truncation
     • When data must be shortened to fit
       • result in missing text/incorrect value