IP Address Classification

0、概要

An IP address is 32-bit long. IP addresses are classified into A,B,C,D,and E classes,as shown in the figure below.
Please determine the class of an input IP address and obtain the corresponding IP address information according to the input 32-bit IP address.?
For IP addresses of A,and C classes,the network number and host number are required. For class D addresses,the multicast address is required. Class E addresses are reserved for future use and do not require the network number,host number,or multicast address.?

1.A类地址：1.0.0.0~127.255.255.255
当中127开头的地址被保留，用作測试仅仅用。10.0.0.0~10.255.255.255被保留为私有地址使用。

这样A类地址就仅仅有1.0.0.0~9.255.255.255和11.0.0.0~126.255.255.255能够正经常使用了。

2.B类地址：128.1.0.0~191.255.255.255
当中172.16.0.0和172.31.255.255保留为私有网络的使用，互联网上不使用。

3.C类地址：192.0.1.0~223.255.255.255
当中192.168.0.0和192.168.255.255保留为私有网络使用，互联网上不适用。

4.D类地址：224.0.0.0~ 239. 255. 255.255
D类地址用于在IP网络中的组播( multicasting。又称为多目广播)。

5.E类地址：240.0.0.0~255.255.255.255
E类地址保留作研究之用。因此Internet上没有可用的E类地址。

1、要求

/***************************************************************************
Description  
    IP地址长32bit，可分为A/B/C/D/E 5类地址。不同五类地址格式定义见题目描写叙述中的附图。
    
	请依据输入的32bit IP地址，推断IP地址的类别，并获得相应的IP地址信息。
	当中A/B/C类地址。须要获得网络号和主机号。D类地址须要获得多播组号。E类地址不涉及。
Prototype
    int GetIpAddressInfo(unsigned int unIpAddr,IpAddressInfoStru* pAddrInfo)
Input Param 
    unsigned int unIpAddr:  Ip 地址  
Output Param
    IpAddressInfoStru* pAddrInfo:   IP地址信息的结果。IpAddressInfoStru參加定义
    当中：nType 为地址类别。请按枚举IP_ADDR_TYPE返回。
stCompose 为网络号和主机号的结构定义。在A/B/C类地址的时候须要返回。 nMultiBoardNo 为多播组号。在D类地址的时候须要返回。 Return Value int -1: 失败 0: 成功 ****************************************************************************/

2、方法一

#include <stdio.h>
#include <bitset>
using std::bitset;

/*IP地址类别*/
typedef enum
{
	IP_ADDR_TYPE_A,/* A类IP地址*/
	IP_ADDR_TYPE_B,/* B类IP地址*/
	IP_ADDR_TYPE_C,/* C类IP地址*/
	IP_ADDR_TYPE_D,/* D类IP地址*/
	IP_ADDR_TYPE_E    /* E类IP地址*/
}IP_ADDR_TYPE;

typedef struct
{
	int nNetworkNo;    /* 网络号*/
	int nHostNo;       /* 主机号*/
}IpComposeStru;

typedef struct
{
	int nType;        /*IP地址类型*/
	union
	{
		IpComposeStru stCompose; /*IP地址子信息*/ 
		int nMultiBoardNo;       /*多播组号*/
	}IpSubsetInfo;
}IpAddressInfoStru;

// 方法1
int GetIpAddressInfo(unsigned int unIpAddr,IpAddressInfoStru* pAddrInfo)
{
	/*在这里实现功能*/
	if (pAddrInfo == NULL)
	{
		return -1;
	}

	bitset<32> bitIpAddr = 0;
	bitIpAddr = unIpAddr;

	if (!bitIpAddr.test(31))
	{
		pAddrInfo->nType = IP_ADDR_TYPE_A;
		bitset<7> bitNetworkNo;
		for (int i = 0; i < 7; i++)
		{
			bitNetworkNo[i] = bitIpAddr[24 + i];
		}
		bitset<24> bitHostNo;
		for (int i = 0; i < 24; i++)
		{
			bitHostNo[i] = bitIpAddr[i];
		}
		pAddrInfo->IpSubsetInfo.stCompose.nNetworkNo = bitNetworkNo.to_ulong();
		pAddrInfo->IpSubsetInfo.stCompose.nHostNo = bitHostNo.to_ulong();
		
		return 0;
	}
	else if (!bitIpAddr.test(30))
	{
		pAddrInfo->nType = IP_ADDR_TYPE_B;
		bitset<14> bitNetworkNo;
		for (int i = 0; i < 14; i++)
		{
			bitNetworkNo[i] = bitIpAddr[16 + i];
		}
		bitset<16> bitHostNo;
		for (int i = 0; i < 16; i++)
		{
			bitHostNo[i] = bitIpAddr[i];
		}
		pAddrInfo->IpSubsetInfo.stCompose.nNetworkNo = bitNetworkNo.to_ulong();
		pAddrInfo->IpSubsetInfo.stCompose.nHostNo = bitHostNo.to_ulong();

		return 0;
	}
	else if (!bitIpAddr.test(29))
	{
		pAddrInfo->nType = IP_ADDR_TYPE_C;
		bitset<21> bitNetworkNo;
		for (int i = 0; i < 21; i++)
		{
			bitNetworkNo[i] = bitIpAddr[8 + i];
		}
		bitset<8> bitHostNo;
		for (int i = 0; i < 8; i++)
		{
			bitHostNo[i] = bitIpAddr[i];
		}
		pAddrInfo->IpSubsetInfo.stCompose.nNetworkNo = bitNetworkNo.to_ulong();
		pAddrInfo->IpSubsetInfo.stCompose.nHostNo = bitHostNo.to_ulong();
		
		return 0;
	}
	else if (!bitIpAddr.test(28))
	{
		pAddrInfo->nType = IP_ADDR_TYPE_D;
		bitset<28> bitMultiBoardNo;
		for (int i = 0; i < 28; i++)
		{
			bitMultiBoardNo[i] = bitIpAddr[i];
		}
		pAddrInfo->IpSubsetInfo.nMultiBoardNo = bitMultiBoardNo.to_ulong();

		return 0;
	}
	else if (!bitIpAddr.test(27))
	{
		pAddrInfo->nType = IP_ADDR_TYPE_E;

		return 0;
	}
}

3、方法二

#include <stdio.h>

/*IP地址类别*/
typedef enum
{
	IP_ADDR_TYPE_A,/* D类IP地址*/
	IP_ADDR_TYPE_E /* E类IP地址*/
}IP_ADDR_TYPE;

typedef struct
{
	int nNetworkNo; /* 网络号*/
	int nHostNo; /* 主机号*/
}IpComposeStru;

typedef struct
{
	int nType; /*IP地址类型*/
	union
	{
		IpComposeStru stCompose; /*IP地址子信息*/
		int nMultiBoardNo; /*多播组号*/
	}IpSubsetInfo;
}IpAddressInfoStru;

//方法2
int GetIpAddressInfo(unsigned int unIpAddr,IpAddressInfoStru* pAddrInfo)
{
	/*在这里实现功能*/
	if (pAddrInfo == NULL)
	{
		return -1;
	}
	if (!((unIpAddr)&(0x80000000)))
	{
		pAddrInfo->nType = IP_ADDR_TYPE_A;

		unsigned int bitNetworkNo;
		unsigned int bitHostNo;
		unsigned int bittemp = unIpAddr;
		bitHostNo = bittemp&(0x00FFFFFF);
		bitNetworkNo = bittemp>>24;
		pAddrInfo->IpSubsetInfo.stCompose.nNetworkNo = bitNetworkNo;
		pAddrInfo->IpSubsetInfo.stCompose.nHostNo = bitHostNo;
		return 0;
	}
	else if (!((unIpAddr)&(0x40000000)))
	{
		pAddrInfo->nType = IP_ADDR_TYPE_B;

		unsigned int bitNetworkNo;
		unsigned int bitHostNo;
		unsigned int bittemp = unIpAddr;
		bitHostNo = bittemp&(0x0000FFFF);
		bitNetworkNo = ((bittemp>>16)&(0x00003FFF));
		pAddrInfo->IpSubsetInfo.stCompose.nNetworkNo = bitNetworkNo;
		pAddrInfo->IpSubsetInfo.stCompose.nHostNo = bitHostNo;
		return 0;
	}
	else if (!((unIpAddr)&(0x20000000)))
	{
		pAddrInfo->nType = IP_ADDR_TYPE_C;

		unsigned int bitNetworkNo;
		unsigned int bitHostNo;
		unsigned int bittemp = unIpAddr;
		bitHostNo = bittemp&(0x000000FF);
		bitNetworkNo = ((bittemp>>8)&(0x001FFFFF));
		pAddrInfo->IpSubsetInfo.stCompose.nNetworkNo = bitNetworkNo;
		pAddrInfo->IpSubsetInfo.stCompose.nHostNo = bitHostNo;
		return 0;
	}
	else if (!((unIpAddr)&(0x10000000)))
	{
		pAddrInfo->nType = IP_ADDR_TYPE_D;

		unsigned int bitMultiBoardNo;
		unsigned int bittemp = unIpAddr;
		bitMultiBoardNo = bittemp&(0x0FFFFFFF);
		pAddrInfo->IpSubsetInfo.nMultiBoardNo = bitMultiBoardNo;
		return 0;
	}
	else if (!((unIpAddr)&(0x08000000)))
	{
		pAddrInfo->nType = IP_ADDR_TYPE_E;
		return 0;
	}
	return -1;
}