Paper 2 Revision

Paper 2 Revision

1. Truth tables

   • OR table = at least 1 input must be positive in order for the output to be positive
   • AND table = both inputs must be positive in order for the output to be positive
   • NOT table = Outputs the opposite from the input

2. differences between compiler and interpreter

   • COMPILER = Translates entire source code at once, creates an executable file, good for final testing and is needed to distribute program, shows list of errors at end of translating the high level code
   • INTERPRETER = translates source code one line at a time, does not create an executable file, good for iterative testing, stops translating when encounters an error in the high level code

3. Functions and procedures and parameters and arguments

   • FUNCTIONS = always return a value, must take atleast 1 parameter/argument and when a function is called it must be assigned to a variable, or used in a staement
   • PROCEDURES = do not return values, do not have to take parameters/arguments however they can take them if needed
   • PARAMETERS = The variable
   • ARGUMENTS = the value within the variable

4. Benefits of subprograms

   • Allows you to reuse same code over again in different programs which makes it quicker to develop new programs and allows programmers to build on existing code for different projects
   • can write programs in less lines of code which means that you avoid code repitition, can debug more efficiently due to not repeating errors, code is easier to maintain and understand
   • programs broken down into smaller parts(Decompostion) which makes the testing process quicker
   • work can be split up within development teams which makes production more efficient due to skill sets of different programmers

5. Maintainability

   • Use comments to explain how a certain part of the program works
   • use indentation to make it easier to read by organisation
   • Use constants so values can be updated easily on one line instead of having to update it on multiple lines