python queue and stack module code example
Example: python list as stack and queue
def isEmpty(stk): # checks whether the stack is empty or not
if stk==[]:
return True
else:
return False
def Push(stk,item): # Allow additions to the stack
stk.append(item)
top=len(stk)-1
def Pop(stk):
if isEmpty(stk): # verifies whether the stack is empty or not
print("Underflow")
else: # Allow deletions from the stack
item=stk.pop()
if len(stk)==0:
top=None
else:
top=len(stk)
print("Popped item is "+str(item))
def Display(stk):
if isEmpty(stk):
print("Stack is empty")
else:
top=len(stk)-1
print("Elements in the stack are: ")
for i in range(top,-1,-1):
print (str(stk[i]))
# executable code
if __name__ == "__main__":
stk=[]
top=None
Push(stk,1)
Push(stk,2)
Push(stk,3)
Push(stk,4)
Pop(stk)
Display(stk)