Added Stack Implementation

Data Structures/Stack/Stack.js

@@ -0,0 +1,69 @@
+/* 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();