import java.util.ArrayList;
import java.util.EmptyStackException;
/**
* Created by Lxx on 2017/4/29.
*/
public class Stack {
public ArrayList array;
public int count;
public Stack(){
array = new ArrayList();
}
public void push (Object o){
count ++ ;
array.add(o);
}
public Object pop(){
count -- ;
Object o = array.get(count);
array.remove(o);
return o;
}
public Object peek(){
if(count == 0){
throw new EmptyStackException();
}
return array.get(array.size()-1);
}
public boolean isEmpty(){
return array.size() == 0;
}
public int size(){
return count;
}
public String toString(){
StringBuilder string = new StringBuilder();
Stack s = new Stack();
int size = this.size();
for(int i = 0;i<size;i++){
string.append(this.peek().toString());
if(i < size -1)
string.append(",");
s.push(this.pop());
}
while (!s.isEmpty()){
this.push(s.pop());
}
return string.toString();
}
}