# Python program to reverse a string using stack 

# Function to create an empty stack. 
# It initializes size of stack as 0 
def createStack(): 
	stack=[] 
	return stack 

# Function to determine the size of the stack 
def size(stack): 
	return len(stack) 

# Stack is empty if the size is 0 
def isEmpty(stack): 
	if size(stack) == 0: 
		return True 

# Function to add an item to stack . 
# It increases size by 1 
def push(stack,item): 
	stack.append(item) 

#Function to remove an item from stack. 
# It decreases size by 1 
def pop(stack): 
	if isEmpty(stack): return
	return stack.pop() 

# A stack based function to reverse a string 
def reverse(string): 
	n = len(string) 
	
	# Create a empty stack 
	stack = createStack() 

	# Push all characters of string to stack 
	for i in range(0,n,1): 
		push(stack,string[i]) 

	# Making the string empty since all 
	#characters are saved in stack 
	string="" 

	# Pop all characters of string and 
	# put them back to string 
	for i in range(0,n,1): 
		string+=pop(stack) 
		
	return string 
	
# Driver program to test above functions 
string="GeeksQuiz"
string = reverse(string) 
print("Reversed string is " + string) 

# This code is contributed by Yash