Reverse a queue using stack

//C Program
//Reverse a queue using stack
#include <stdio.h>

#include <stdlib.h> //for malloc function

//Create structure of Queue
struct MyQueue
{
	int data;
	struct MyQueue *next;
};
struct MyStack
{
	struct MyQueue *element;
	struct MyStack *next;
};
// Define some global variables which is directly 
// will be accessed within below defined function.
// Queue pointer variables.
struct MyQueue *head = NULL, *tail = NULL;
//Stack pointer variable
struct MyStack *top = NULL;
//This function are add new element into queue
void enqueue(int value)
{
	//Create a dynamic node
	struct MyQueue *node = (struct MyQueue *) malloc(sizeof(struct MyQueue));
	if (node == NULL)
	{
		printf("Memory overflow\n");
	}
	else
	{
		//set new node data
		node->data = value;
		node->next = NULL;
		if (head == NULL)
		{
			//add first element into queue
			head = node;
			tail = node;
		}
		else
		{
			//add node at the end using tail pointer
			tail->next = node;
			tail = node;
		}
	}
}
//Delete a element into queue
int dequeue()
{
	int data = -1;
	if (head == NULL)
	{
		printf("Empty Queue\n");
		return data;
	}
	//Get the deleted node
	struct MyQueue *temp = head;
	data = temp->data;
	//visit to next node of queue
	head = head->next;
	if (head == NULL)
	{
		//When deleting a last node of linked list
		tail = NULL;
	}
	free(temp);
	temp = NULL;
	return data;
}
void push(struct MyQueue *node)
{
	struct MyStack *new_node = (struct MyStack *) malloc(sizeof(struct MyStack));
	if (new_node)
	{
		new_node->element = node;
		new_node->next = top;
		top = new_node;
	}
}
// This function are remove top node into stack and return 
// the queue element .
// Basically we are returns a value of data value but here added 
// a actual queue element into stack. 
// so return this node element
struct MyQueue *pop()
{
	if (top != NULL)
	{
		struct MyQueue *result = top->element;
		struct MyStack *temp = top;
		top->element = NULL;
		top = top->next;
		free(temp);
		temp = NULL;
		return result;
	}
	return NULL;
}
//Display all queue element
void print_queue()
{
	struct MyQueue *temp = head;
	while (temp != NULL)
	{
		printf("%d  ", temp->data);
		temp = temp->next;
	}
	printf("\n");
}
//This method are reverse the queue elements 
void reverse()
{
	struct MyQueue *temp = head;
	//First add all queue elements into stack
	while (head != NULL)
	{
		temp = head;
		//add current head node into stack
		push(head);
		//visit to next upcoming node
		head = head->next;
		//Note that we are not delete queue element 
		// so added element are hold next node information to queue 
		// so remove next node information
		// set nil
		temp->next = NULL;
	}
	//add stack elements into the actual queue
	while (top != NULL)
	{
		if (head == NULL)
		{
			// pop a stack element
			// And set that top queue element as first node of queue
			head = pop();
			// Because that is first node of queue.
			// So tail node is also hold the information of first node.
			tail = head;
		}
		else
		{
			//Add new stack top element into queue tail section
			tail->next = pop();
			//make a new tail node
			tail = tail->next;
		}
	}
}
int main()
{
	//Add queue elements
	enqueue(1);
	enqueue(2);
	enqueue(3);
	enqueue(4);
	enqueue(5);
	enqueue(9);
	enqueue(11);
  	printf("Before : ");
	//Display all queue elements
	print_queue();
	reverse();
  	printf("After : ");
	//Display all queue elements
	print_queue();
	return 0;
}

Output

Before : 1  2  3  4  5  9  11
After : 11  9  5  4  3  2  1