/*使用栈stack类的实现*/
function stack() {
  this.dataStore = [];//保存栈内元素，初始化为一个空数组
  this.top = 0;//栈顶位置，初始化为0
  this.push = push;//入栈
  this.pop = pop;//出栈
  this.peek = peek;//查看栈顶元素
  this.clear = clear;//清空栈
  this.length = length;//栈内存放元素的个数
}
function push(element){
  this.dataStore[this.top++] = element;
}
function pop(){
  return this.dataStore[--this.top];
}
function peek(){
  return this.dataStore[this.top-1];
}
function clear(){
  this.top = 0;
}
function length(){
  return this.top;
}
/*使用栈判断给定字符串是否是回文的算法*/
function isPalindrome(word){
  var s = new stack();
  for(var i = 0;i < word.length;i++){
    s.push(word[i]);
  }
  var rword = "";
  while(s.length() > 0){
    rword += s.pop();
  }
  if(word == rword){
    return true;
  }else{
    return false;
  }
}
var word1 = "racecar";
if(isPalindrome(word1)){
  console.log(word1 + " is a palindrome")//racecar is a palindrome
}