## stacks 

<br>

### stacks

<br>

* last in, first out structures (LIFO)
* useful in certain recursive algorithms, where you can push temp data as you recurse, and remove them from the (memory or data structure) stack as you backtrace.


<br>

---

## examples

<br>

#### `stack.py`

<br>

```python
python3 stack.py

Testing Stack...

Stack: [12, 13, 14, 15, 16, 17, 18, 19, 20]
Stack size: 9
Stack peek: 20
Stack is empty: False
Stack min: 12

Popping...
20
19
18
17
16
Stack: [12, 13, 14, 15]
```