How to work with queues and stacks

How to work with a stack

      $names = array('Mike', 'Joel', 'Anne'); 

      array_push($names, 'Ray'); 

      $next = array_pop($names); 

      echo $next;
      Ray

How to work with a queue

      $names = array('Mike', 'Joel', 'Anne');

      array_push($names, 'Ray'); // $names is Mike, Anne, Joel, Ray

      $next = array_shift($names); // $names is Anne, Joel, Ray

      echo $next; // displays Mike
      Mike

A stack is a special type of array that implements a last-in, first-out (LIFO) collec-tion of values. You can use the array_push() and array_pop() functions to add and remove elements in a stack.
A queue is a special type of array that implements a first-in, first-out (FIFO) collection of values. You can use the array_push() and array_shift() functions to add and remove elements in a queue.
The functions in this figure modify the array that’s passed to the function. In other words, they don’t return a new array.

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