1.2.4 Computer science

1.2.4 Computer science

1. Programming paradigms

   • Examples
     • Procedural
     • Object oriented
     • Assembly
   • Some can be used to solve all problems but some are better suited than others
   • Features
     • Instructions are given in sequence
     • Selection is used to make choices
     • Programs are broken down into blocks called procedures or functions
     • They tell a computer what to do step by step
     • They are laid out in an order of sequence selection and iteration
     • Code is developed in a modular way

2. Assembly languages

   • Features
     • Mnemonics are used to place machine code instructions
     • They can be executed directly as machine code
     • They consist of an opcode and an operand
     • The instruction set is specific to the processor
   • LMC
     • A set of instructions that is very close to machine code
     • There are 9 instructions
       • Add
       • Subtract
       • Store
       • Load
       • Branch
       • Branch on zero
       • Branch on positive
       • Input
       • Output
       • Halt / Stop
       • Data storage location

3. Addressing

   • Immediate
     • The value in the address part of the instruction is the data to be used
     • Memory does not have to be searched
   • Direct
     • The address part of the instruction is the address of the data needed
   • Indirect
     • The address instruction is where you will find the address of the data needed
     • Larger addresses can be used
   • Indexed
     • An index register contains a value that needs to be added to the address to find the value

4. Object oriented programming

   • Classes
     • Main sections
       • Class name
       • Attributes
       • Methods
     • OOP methods
       • Instantiation
         • The process of creating an object from a class
       • Inheritance
         • A subclass is created from a superclass
         • Attributes and methods can be kept and added
         • Multiple subclasses can be made from a superclass
       • Polymorphism
         • Programs can use variables if different types at different times
         • It is the ability to present the same interface for several different data types
       • Encapsulation
         • The protection and methods of an object so they cant be accessed by other objects
         • An attempt to change an encapsulated attribute or method will result in an error