- Show, step by step, how we can use a stack to compute the value of the following arithmetic expression in postfix: 234*+5-
- Show, step by step, how a queue implemented as a circular array will look after the following sequence of operations:
initialize(); enqueue(1); enqueue(2); dequeue(); enqueue(3); enqueue(4); dequeue(); enqueue(5); enqueue(6);

assume that we use arrays of size 4.