class 12 cs term 2 practical
def check_stack_isEmpty(stk):
if stk==[]:
return True
else:
return False
s=[] # An empty list to store stack elements, initially its empty
top = None # This is top pointer for push and pop operation
def main_menu():
while True:
print("Stack Implementation")
print("1 - Push")
print("2 - Pop")
print("3 - Peek")
print("4 - Display")
print("5 - Exit")
ch = int(input("Enter the your choice:"))
if ch==1:
el = int(input("Enter the value to push an element:"))
push(s,el)
elif ch==2:
e=pop_stack(s)
if e=="UnderFlow":
print("Stack is underflow!")
else:
print("Element popped:",e)
elif ch==3:
e=pop_stack(s)
if e=="UnderFlow":
print("Stack is underflow!")
else:
print("The element on top is:",e)
elif ch==4:
display(s)
elif ch==5:
break
else:
print("Sorry, You have entered invalid option")
def push(stk,e):
stk.append(e)
top = len(stk)-1
def display(stk):
if check_stack_isEmpty(stk):
print("Stack is Empty")
else:
top = len(stk)-1
print(stk[top],"-Top")
for i in range(top-1,-1,-1):
print(stk[i])
def pop_stack(stk):
if check_stack_isEmpty(stk):
return "UnderFlow"
else:
e = stk.pop()
if len(stk)==0:
top = None
else:
top = len(stk)-1
return e
def peek(stk):
if check_stack_isEmpty(stk):
return "UnderFlow"
else:
top = len(stk)-1
return stk[top]