栈

概念

栈是遵从一种先进后出（LIFO）的有序集合

实现栈

function Stack() {
    let items = [];
  // 向栈内添加元素
  this.push = function(element) {
      items.push(element);
  }
  // 从栈顶移除元素
  this.pop = function() {
      return items.pop();
  }
  // 查看栈顶元素
  this.peek = function() {
      return items[items.length - 1];
  }
  // 检查栈是否为空
  this.isEmpty = function() {
      return items.length == 0;
  }
  // 查看栈的长度
  this.size = function() {
      return items.length;
  }
  // 清空栈
  this.clear = function() {
      items = [];
  }
  // 打印栈元素
  this.print = function() {
      console.log(items.toString());
  }
}

栈的应用

10进制转2进制

function divideBy2(decNumber) {
    var remStack = new Stack();
  var rem;
  var binaryString = '';
  while(decNumber > 0) {
      rem = Math.floor(decNumber % 2);
    remStack.push(rem);
    decNumber = Math.floor(decNumber / 2);
  }
  while(!remStack.isEmpty()) {
      binaryString += remStack.pop().toString();
  }
  return binaryString;
}