数组实现栈和队列

package com.harrison.class02;
//数组实现队列
public class Code05_RingArray {
  public static class MyQueue{
    private int[] arr;
    private int pushIndex;//end
    private int pollIndex;//begin
    private int size;
    @SuppressWarnings("unused")
    private final int limit;
    public MyQueue(int limit) {
      arr=new int[limit];
      pushIndex=0;
      pollIndex=0;
      size=0;
      this.limit=limit;
    }
    public void push(int value) {
      if(size==limit) {
        throw new RuntimeException("队列满了，不能再加了！");
      }
      size++;
      arr[pushIndex]=value;
      pushIndex=nextIndex(pushIndex);
    }
    public int pop() {
      if(size==0) {
        throw new RuntimeException("队列空了，不能再拿了！");
      }
      size--;
      int ans=arr[pollIndex];
      pollIndex=nextIndex(pollIndex);
      return ans;
    }
    public boolean isEmpty() {
      return size==0;
    }
    public int nextIndex(int i) {
      return i<size-1?i+1:0;
    }
  }
}