// Copyright 2020 Rajdeep Chandra // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. var Stack = function() { this.count = 0; this.storage = {}; // creating a function to add a value to the stack this.push = function(value) { this.storage[this.count] = value; this.count++; } // creating a function to remove a value from the stack this.pop = function(){ if(this.count === 0){ return undefined } this.count-- ; var result = this.storage[this.count]; delete this.storage[this.count]; return result; } // creating a function to know the vlaue of items in the stack this.size = function() { return this.count; } // creating a function to see the last element in the stack this.peek = function(){ return this.storage[this.count - 1] } } var newStack = new Stack(); newStack.push(1); newStack.push(2); console.log(newStack.peek()); console.log(newStack.pop()); console.log(newStack.peek());