2020年7月6日 栈 代码

栈

class Untitled {
	//压入元素
	//
	static int[] elements = new int[0];
	public static void push(int element)
	{
		int[] newarr = new int[elements.length +1];
		for(int i=0;i<elements.length;i++)
		{
			newarr[i] = elements[i];
		}
		newarr[elements.length] = element;
		elements = newarr;
	}
	//去除元素
	public static void pop()
	{
		if(elements.length==0)
		{
			throw new RuntimeException("栈为空");
		}
		int[] newarr = new int[elements.length -1];
		for(int i=0;i<elements.length-1;i++)
		{
			newarr[i] = elements[i];
		}
		elements = newarr;
	}
	//查看栈顶元素
	public static int find()
	{
	 return	elements[elements.length-1];
	}
	
	public static void main(String[] args) {
		//push(7);
		//push(8);
		//push(9);
		//System.out.println(find());
		pop();
		//System.out.println(find());
	}
}