class Stack {
   constructor() {
      this.count=0
      this.items = {}
            }
   push(element) {
      this.items[this.count]=element
      this.count++
            }
    pop() {
       if(this.isEmpty()){
           return undefined
          }
       this.count--
       const result=this.items[this.count]
       delete this.items[this.count]
       return result
            }
    peek() {
          if(this.isEmpty()){
               return undefined
               }
         return this.items[this.count-1]
            }
    isEmpty() {
         return this.count===0
            }
    clear() {
        this.items={}
        this.count=0
          }
    size() {
       return this.count
           }
    toString(){
       if(this.isEmpty()){
        return undefined
               }
         let objectString=`${this.items[0]}`
          for(let i=1;i<this.count;i++){
               objectString=`${objectString},${this.items[i]}`
               }
         return objectString
            }
        }
 
  const stack = new Stack()
  stack.push(23)
  stack.push(34)
  stack.push(80)
  console.log( stack.pop())
  console.log(stack.peek())
  console.log(stack.isEmpty())
  console.log(stack.size())
  console.log(stack.toString())