-
Notifications
You must be signed in to change notification settings - Fork 0
/
program15.py
67 lines (57 loc) · 1.31 KB
/
program15.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
# Write a program to implement stack in python using list.
def is_empty(stack: list) -> bool:
'''
Checks if the stack is empty.
'''
if len(stack) == 0:
return True
else:
return False
def push(item, stack: list):
'''
Pushes an element to the top of stack.
'''
global top
stack.append(item)
print("Pushed an element.")
top += 1
def pop(stack: list):
'''
Pops an element from the top of stack and returns it.
'''
global top
if is_empty(stack):
return "Underflow Error."
else:
item = stack.pop()
print("Popped an element.")
top -= 1
return item
def peek(stack: list):
'''
Returns the top element of stack without popping.
'''
if is_empty(stack):
return "Underflow."
return stack[top]
def display(stack: list):
'''
Displays the entire stack.
'''
if is_empty(stack):
print("Stack is empty.")
else:
print("Elements:")
for a in range(top, -1, -1 ):
if a == top:
print(stack[top], "<-- top" )
else:
print(stack[a])
stack = []
top = -1
push(19, stack)
push(100, stack)
push(0, stack)
print("Popped element:", pop(stack))
print("Peeking stack:", peek(stack))
display(stack)