Push n Pop Calculator

A calculator can be implemented easily with only using a stack and some minor CPU calculations.

The calculations must all be done in reverse polish notation. So, a calculation like: (2+5) * (1+3) turns into 2 5 + 1 3 + *

Now the program pseudocode looks like this:

while (there is still an operation/operand){
	if (operand){
		push operand;
	}
	else if (operation){
		pop last 2 oerands;
		do operation;
		push result;
	}
	else {
		error;
	}
}