栈

先入的后出

 

 

public class stack {
    public static void main(String[] args) {
        stack s=new stack(4);
        s.push(1);
        s.list();
//        String key="";
//        boolean loop=true;
//        Scanner scanner=new Scanner(System.in);
//        while(loop){
//
       }
    int maxsize;
    int[] stack;
    int top=-1;//指向栈顶，初始化为-1
    public stack(int maxsize){
        this.maxsize=maxsize;
        stack=new int[this.maxsize];

    }
    public boolean isFull(){
        return top==maxsize-1;
    }
    public boolean isEmpty(){
        return top==-1;
    }
    public void push(int value){
        if(isFull()){
            System.out.println("full");
        }
        top++;
        stack[top]=value;

    }
    public int pop(){
        if(isEmpty()){
            System.out.println("null");
            throw new RuntimeException();
        }
        int value=stack[top];
        top--;
        return value;
    }
    public void list(){
        if(isEmpty()){
            System.out.println("null");
        }
        for(int i=top;i>=0;i--){
            System.out.println(stack[i]);
        }
    }

   }