北邮 BOJ 131 IP数据包解析

思路：

图都没有，还好初试有计算机网络

解答：

package bupt;

import java.util.Scanner;

/*
*@author:Totoro
*@createDate:2020年3月18日下午5:54:34
*/
public class IP数据包解析
	{

	public static void main(String[] args)
		{
		Scanner cin=new Scanner(System.in);
		int T=cin.nextInt();
		cin.nextLine();
		String head_package;
		String[] head;
		for(int t=1;t<=T;++t)
			{
			head_package=cin.nextLine();
			head=head_package.split(" ");
			int len=Integer.valueOf(head[2]+head[3],16);
			int[] source=new int[4];
			for(int i=0;i<4;++i)
				source[i]=Integer.valueOf(head[12+i],16);
			int[] destination=new int[4];
			for(int i=0;i<4;++i)
				destination[i]=Integer.valueOf(head[16+i],16);
			int source_port=Integer.valueOf(head[20]+head[21],16);
			int destination_port=Integer.valueOf(head[22]+head[23],16);
			System.out.println("Case #"+t);
			System.out.println("Total length = "+len+" bytes");
			System.out.println("Source = "+source[0]+"."+source[1]+"."+source[2]+"."+source[3]);
			System.out.println("Destination = "+destination[0]+"."+destination[1]+"."+destination[2]+"."+destination[3]);
			System.out.println("Source Port = "+source_port);
			System.out.println("Destination Port = "+destination_port);
			System.out.println();
			}
		}

	}