Topic 7- Programming

Topic 7- Programming

1. High level language

   • Is a programming language that allows code to be written
   • It's similar to human language
   • Some people prefer them as they're easier to learn and code
   • They're used when execution speed is not critical
   • Examples include
     • Basic
     • Java
     • Pascal
   • Have to be converted into machine code to be executed

2. Machine code

   • Opposite to high level language
   • Doesn't resemble human language
   • Made up of bit codes
   • Can be directly executed by the CPU
   • Primarily coded first when execution level is critical

3. Variables

   • A variable may be required to store data that can change
   • Variables are given identifiers (names) that reflect the data being stored
   • Example of a identifer would be txt_Name for a name. This is a self documenting identifier

4. Constrasts

   • Used in programming to store data that doesn't change
   • Also given self documenting identifiers
   • Example of a constant would be Pi = 3.14, this is a self-documenting identifier that does not change.

5. Types of variables

   • Local- variable that is defined within a sub procedure and is only accessible from within the same sub procedure. Known as scope.
   • Global- variable that has a larger scope as it is defined globally and is accessible from anywhere in the program
   • Static- stored in a location in memory and have a lifespan that lasts the entire time that program is running. E.g. if you assign a number to 2.1, it will remain constant
   • Dynamic- it is assigned a new location in memory and has a lifespan that ends when the sub procedure in which it was defined, ends.

6. Pros and cons of different variables

   • Advantage global over local is that sometimes it can be more efficient way or ensuring data is accessible to all sub procedures