Programming

Programming

1. Algorithm

   • Solving problems 1 step at a time
   • Processors can only process 1 instruction at a time
   • Mainly expressed as a flow chart
     • Make sure you know the symbols

2. Pseudocode

   • Used for planning algorithm
   • Should allow a programmer to write it in any language
   • Key words written in capital letters (eg INPUT,IF,WHILE)

3. High level/low level programming

   • High level has to be translated
     • eg Python, BASIC, javascript
     • Uses language that is easier to understand by humans
     • Has to be translated
   • Low level is understood by the processor
     • Assembly Language
       • Written as each instruction would be processed
       • eg INP, LDA, OUT
       • Codes specific to a type of processor
     • Machine code
       • Binary codes for each instruction and register location

4. Control flow

   • Iteration
     • Loops
       • WHILE or FOR
   • Sequencing
     • The order through an algorithm
   • Selection
     • IF THEN ELSE

5. Testing

   • Logical error
     • Human error with the construction of the algorithm
   • Run-Time-Error
     • An error in the program eg stuck in a loop
   • Syntax error
     • Not a correct command for the coding language being used

6. Data types

   • integers and real numbers
     • Integer is a whole number
     • Real (sometimes called float) can have decimal places
   • Variable or constant
     • Constant stays the same eg pi
     • Variable changes during the program eg score in a game
   • Operations are mathematical symbols eg <> + -
   • Arrays are lists of the same data type

7. Translation

   • Interpreter
     • Executes the source code direcly
     • Used when creating a program
     • Would be used on open source software
   • Complier
     • Would be used for proprietary software
     • Creates an executable file to run the program
     • Once it is complied it doesnt need the original source code
   • Assembier
     • Turns assembly language into machine code
     • Only can be used in low level programming