js面向对象写法及栈的实现

 function Stack() {
   this.dataStore = [];
   this.top = 0; //指向栈顶的位置
   this.push = push;
   this.pop = pop;
   this.peek = peek;
   this.clear = clear;
   this.length = length;

   function push(element) {
     this.dataStore[this.top++] = element; //先赋值后++
   }

   function peek() {
     return this.dataStore[this.top - 1];
   }

   function pop() {
     return this.dataStore[--this.top]; //先--运算
   }

   function clear() {
     this.top = 0;
   }

   function length() {
     return this.top;
   }
 }

 var s = new Stack();
 s.push("David");
 s.push("Raymond");
 s.push("Bryan");
 console.log(s);
 console.log("length: " + s.length()); 

 

注意：

这样的一步操作arr[i++]="ddd";----》这里的执行顺序是：先执行赋值后进行的++运算

等价于下面的两布操作：

arr[i] = "ddd";

i++;

 

 

//这样写才是先执行++运算

arr[++i]="ddd";