Methods I might use to access variables with a simple interpreter?

Projects Programming
2

Dyslexicbloke:

  1. Use a case statement, there would need to be a case for every variable I want to access.
    That seems simple and is probably fast but I doubt its the bast way.

Fast? Probably not. The GCC-AVR compiler that comes with Arduino expands switch/case to a series of if/else.

A simple speed improvement is to put the most likely cases at the top.

  1. Use a two arrays one hold the place-holder text and a second, with the same ordinal, to hold a pointer to the value.
    I could loop through the first until I found the required name and then get the pointer from the second, using it to return the value.

Hashing. Hash function. Hash table.

If you are concerned about look-up performance...
http://burtleburtle.net/bob/hash/perfect.html

How do I go about doing this on an Arduino
a. Getting a pointer to a variable?

& MyVariable;

b. using the pointer to return the variable value

int MyVariable;

void loop( void )
{
  int * MyPointer;

  MyPointer = & MyVariable;

  Serial.println( * MyPointer );
}

Do global variables always stay in the same place in memory once they have been created

Yes.

or do I need to do something to ensure that?

No.