SOLVED

Solution: use pointers to allocate var names to memory address, then declare only the ones needed in active code, others don't get loaded into ram

// 


I have 2 classes, class A and class B

think of them as 2 different modes the program can operate in

each time the program starts, I want to choose either class A or class B
whichever I use, the other will never need to be used while the program is running

So both class A and B will exist in memory storage, but I only ever want to Load one of them into Dynamic Memory
class A and class B both take up ~80% of my dynamic memory, but only ~5% of static memory (let's say)
So I can't load both at once, and I don't want or need to, because once the program is running I only need to be in Mode A or Mode B

My issue is that when I declare Class A, and Class B as variables, they both immediately get loaded into dynamic memory and I run out of memory 

I tried using preprocessor code to conditionally declare 1 variable or the other, but then later in my code when I reference the unused class, I get compiler errors, IE 

if(inModeA)
{

	ClassA.run();

} else if (inModeB) {

	ClassB.run();

}

ERROR: ClassB doesn't exist

(of course, the line of code referencing classB would never actually be run in use because it would be in mode A, but the compiler doesn't like non existent classes)