/* Stack!!
* A stack is exactly what it sounds like. An element gets added to the top of
* the stack and only the element on the top may be removed. This is an example
* of an array implementation of a Stack. So an element can only be added/removed
* from the end of the array.
*/

// Functions: push, pop, peek, view, length

//Creates a stack constructor
var Stack = (function () {

  function Stack() {
    //The top of the Stack
    this.top = 0;
    //The array representation of the stack
    this.stack = new Array();
  }

  //Adds a value onto the end of the stack
  Stack.prototype.push = function (value) {
    this.stack[this.top] = value;
    this.top++;
  };

  //Removes and returns the value at the end of the stack
  Stack.prototype.pop = function () {
    if (this.top === 0) {
      return "Stack is Empty";
    }

    this.top--;
    var result = this.stack[this.top];
    delete this.stack[this.top];
    return result;
  };

  //Returns the size of the stack
  Stack.prototype.size = function () {
    return this.top;
  };

  //Returns the value at the end of the stack
  Stack.prototype.peek = function () {
    return this.stack[this.top - 1];
  }

  //To see all the elements in the stack
  Stack.prototype.view = function () {
    for (var i = 0; i < this.top; i++)
      console.log(this.stack[i]);
  };

  return Stack;

}());

//Implementation
var myStack = new Stack();

myStack.push(1);
myStack.push(5);
myStack.push(76);
myStack.push(69);
myStack.push(32);
myStack.push(54);
console.log(myStack.size());
console.log(myStack.peek());
console.log(myStack.pop());
console.log(myStack.peek());
console.log(myStack.pop());
console.log(myStack.peek());
myStack.push(55);
console.log(myStack.peek());
myStack.view();