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Output:
Displaying the elements in stack
1
4
2
3
Top element of the stack is: 1.
Deleted element is: 1
Displaying the elements in stack
4
2
3
Top element of stack after removing one element is: 4
Data Structure
Stack using Queue
Stack is data structure which follows Last In First Out principle that means the most recent inserted element in stack will be the first element to be removed from stack.Queue is a data structure that follows First In First Out principle that means the element which is inserted at first in the queue will be the first one to remove from queue.So we have to arrange elements in queue in such an order that the element inserted last will be the first element to get remove.
Algorithm:
Take a queue.
Push element in queue
Use a loop to iterate till the queue size()-1,remove the elements and again push it into the queue.This way you will get the last element inserted in queue in the first position.
Pop the first element in queue.
Top will give the first element in queue.
Here is the code :
class Stack
{
queue q;
public:
void Push(int x)
{
// getting the size of queue
int size = q.size();
// pushing our element into the queue
q.push(x);
// using a for loop to iterate through the elements in queue
for (int i = 0; i <= size - 1; i++)
{
/*for size one lesser than the size of queue we are
getting the elements from the front of queue(FIFO) and pushing it back into the same queue.*/
q.push(q.front());
// removing the front element from queue
q.pop();
}
}
int Pop()
{
/*getting element from front of queue as we know queue
follows FIFO principle*/
int element = q.front();
// removing the front element from queue
q.pop();
// giving back the element that we removed from queue
return element;
}
int Top()
{
/*the top element in stack will be the first or front element
of queue*/
return q.front();
}
int Display()
{
queue p = q;
while (!p.empty())
{
int n = p.front();
cout << n << endl;
p.pop();
}
return 0;
}
}; // end of class
int main()
{
// s is an object of class Stack on which we will perform our operations
Stack s;
// pushing element into the stack
s.Push(3);
s.Push(2);
s.Push(4);
s.Push(1);
cout <<”Displaying the elements in stack” << endl;
s.Display();
cout << "Top element of the stack is: " << s.Top() << endl;
cout << "Deleted element is: " << s.Pop() << endl;
cout <<”Displaying the elements in stack” << endl;
s.Display();
cout << "Top element of the stack after removing element is: " << s.Top() << endl;
}
Output:
Displaying the elements in stack
1
4
2
3
Top element of the stack is: 1.
Deleted element is: 1
Displaying the elements in stack
4
2
3
Top element of stack after removing one element is: 4
Automata Fixing