1.创建栈
Stack stack=new Stack(); //Object型
Stack stack = new Stack();//int型
Stack stack = new Stack();
Stack stack = new Stack();//int型
Stack stack = new Stack();//int型
Stack stack = new Stack();//int型
2.判空(true or false)
stack.empty();
3.进栈
stack.push(Object);
4.出栈(获取栈顶值并删除)
stack.pop();
5.栈顶值(只获取不删除)
stack.peek();