用java实现栈和队列(以数组为底层)

1.实现栈

public class StackDemo
{
    private int[] arr;
    private int i=-1;
    
    public StackDemo(int size)
    {
        arr=new in[size];
    }
    //入栈
    public void add(int value)
    {
        if(i==arr.length-1)
        {
            System.out.println("栈已满")；
        }
        i++;
        int date=arr[i];
        return date;
    }
    
    //出栈
    public void get()
    {
        if(i==-1)
        {
            System.out.println("栈已空");
        }
    System.out.println(arr[i]);
    i--;
    return;
}   

测试

public class Test {
	public static void main(String[] args)
	{
		StackDemo stack=new StackDemo(5);
		stack.add(3);
		stack.add(2);
		stack.add(3);
		stack.add(1);
		stack.add(8);
		
		System.out.println(stack.get());
		System.out.println(stack.get());
		System.out.println(stack.get());
		System.out.println(stack.get());
		System.out.println(stack.get());
		
	}
}

输出

8
1
3
2
3

2.队列

public class Queue {
	private int arr[];
	private int c=0;
	private int r=0;
	
	public Queue(int size)
	{
		arr=new int[size];
	}
	
	//入队列
	public void add(int value)
	{	
		//判断是否已满
		if(r-c==arr.length)
		{
			System.out.println("队列已满");
			return;
		}
		arr[r%arr.length]=value;
		r++;
	}
	
	//出队列
	public void get()
	{	
		if(r==c)
		{
			System.out.println("队列已空");
			return;
		}
		System.out.println(arr[c%arr.length]);
		c++;
	}
}

测试

package 栈和队列;

public class Test1 {
	public static void main(String[] args)
	{
		Queue queue=new Queue(5);
		
		queue.add(4);
		queue.add(1);
		queue.add(3);
		queue.add(5);
		queue.add(6);
		
		queue.get();
		queue.get();
		queue.get();
		queue.get();
		queue.get();
	}
}

结果

4
1
3
5
6