My Prompt:

I've defined a new stack based programming language. The instructions are as follows:

A: Duplicate the top of the stack
B: Swap the top two stack elements
+: Add the top two stack elements
any integer: push that integer onto the stack.

For example, if the instructions were 3 A + 4 B then the execution should go as follows
[]
[3]
[3, 3]
[6]
[6, 4]
[4, 6]

Now try evaluating 5 A A + +

GPT-4:

Let's evaluate the given instructions step by step:

Instructions: 5 A A + +

    5: Push 5 onto the stack.
    Stack: [5]

    A: Duplicate the top of the stack (5).
    Stack: [5, 5]

    A: Duplicate the top of the stack (5) again.
    Stack: [5, 5, 5]

    +: Add the top two stack elements (5 + 5).
    Stack: [5, 10]

    +: Add the top two stack elements (5 + 10).
    Stack: [15]

After evaluating the instructions 5 A A + +, the final stack is [15].