2 / 8 Binary Trees & Traversal

Stack Machine Feed

A compiler emits code for a stack machine from this expression tree.

Expression tree: multiply at the root, plus and minus below, four integer leaves * + - 3 4 10 2

The machine has PUSH n, and binary operators that pop two values and push the result. Which token order can it execute straight through, left to right, with no lookahead?

A

3 4 10 2 + - *

B

3 4 + 10 2 - *

C

* + 3 4 - 10 2

D

3 + 4 * 10 - 2