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Implement stack using queue

 

Question :

WAP to implement a stack(LIFO) using queues(FIFO).

If you are not aware of what is stack ?Please see the stack tutorial.

Algorithm :

Iterative Solution :

Declare two queues q1 and q2 .

push(Object obj) 
            Step 1 : Enqueue obj to q2
            Step 2 : One by one dequeue each element from q1 and enqueue to q2.
            Step 3 : Swap the names of q1 and q2

pop()
            Step 1 : Dequeue an item from q1 and return it.

Program :

 

OutPut  :

 
 


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