Programming tools and terms

Programming tools and terms

1. High level languages

   • A programming language that allows code to be written
     • E.G: C++, Java
   • Advantages
     • Easier to understand, learn and program
     • Commands are similar to natural languages
     • Identifiers can be long and meaningful
     • Allows the use of powerful commands that perform complex tasks
   • Used when the execution speed is not critical

2. Machine code

   • Made up entirely up entirely of bit patterns that can be executed directly by the CPU
     • E.G: Opcodes and operands
   • Used when a fast execution speed is critical
   • High level languages need to be converted into machine code before they can be executed by the CPU

3. Variables

   • Variables store data that can change
     • E.G: txt_FirstName
   • They have self-documenting identifiers that reflects the type of data being stored in it
   • Types
     • Local variables
       • A variable that is defined within a sub procedure and is only accessible from within that same sub procedure (its scope)
       • Easier to track changes to a variable and the reason for the changes
     • Global variables
       • A variable that has a larger scope as it is defined globally and is therefore accessible from anywhere in a program
       • Can be the most efficient way of ensuring that an important piece of data is accessible to all sub procedures
     • Static variables
       • Each time a program is run, they are stored in a location in memory.
       • Have a lifespan that lasts the entire time that the program is running.
     • Dynamic variables
       • Each time these are defined they are assigned a new location in memory.
       • Have a lifespan that ends when the sub procedure in which it was defined ends.

4. Constants

   • Constants are used to store data that does not change
     • E.G: Pi = 3.14
   • They are given self-documented identifiers that reflect the data being stored in them