Programming

Programming

1. Algorithms

   • Solving problems 1 at a time
   • Processors can only process 1 instructions at a time
   • Mainly expressed as a flowchart
     • Make sure you know the symbols

2. Pseudocode

   • Used for planning algorithms
   • Should allow a programmer to write it in any language
   • Key words written in capital letter (e.g. INPUT, IF, WHILE)

3. High level and Low level programming

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

4. Translation

   • Assembler
     • Only can be used in low level programming
     • Turns assembly language into machine code
   • Compiler
     • Creates an executable file to run the program
     • Once compiled it doesn't need the original source code
     • Would be used for proprietry standards
   • Interpreter
     • Would be used for open source software
     • Used for creating a program
     • Executes the source code directly

5. Control flow

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

6. Data types

   • Variable or constant
     • Variable changes during the program
     • Constant stays the same
   • Integer and real numbers
     • Integer is a real number
     • Real number (Floats) can have decimal places
   • Arrays are lists of the same data types
   • Operations are mathematical symbols

7. Testing

   • Logical error
     • Human error with the construction of the algorithm
   • Run time error
     • An error in the program e.g. stuck in a loop
   • Syntax error
     • Not a correct command for the coding language being used