====== 8. Zásobník ======

<code python>

class Stack:

    def __init__ (self):

        self.items = [] # prazdny seznam pro udzovani dat

    def push (self, data):

        self.items += [data]

    def pop (self):

        return self.items.pop()

    def is_empty (self):

        return self.items == []

    def size (self):

        return len(self.items)


s = Stack()

s.push (10)
s.push (30)
s.push (40)

while s.is_empty() is not True:
    print (s.pop())

text = 'TE*A*QYS***SEU****NI*O**'

z = Stack()

for x in range(len(text)):
    # print (text[x], end=' ')
    if text[x] >= 'A' and text[x] <= 'Z':
        z.push(text[x])
    if text[x] == '*':
        print(z.pop(), end='')

print()

text = '((()()))'
w = Stack()

for x in range(len(text)):
    if text[x] == '(':
        w.push(text[x])
    if text[x] == ')':
        print('{}-{}'.format(x, w.size()))
        if w.is_empty() or w.pop() != '(':
            print(w.is_empty())
            print('nevalidni')

if w.is_empty() is not True:
    print(w.is_empty())
    print('nevalidni')

</code>