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

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

  //Removes and returns the value at the end of the stack
  this.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
  this.size = function(){
    return this.top;
  }

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

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

//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();