Error: deque iterator not dereferenceable

Question

I\'m trying to create a program that converts an arithmetic expression from infix to postfix form. As long as I don\'t call the \"infixToPostFix\" function, the program runs

Answer 1

You are calling top on empty stack, just follow the code for your test.

1. you start with an empty stack
2. you encounter a VALUE, you don't change stack
3. you encounter an OPERATOR and attempt to access stack.top()