[Huawei Machine Test exercises]54. Determine whether the IP addresses of any two computers belong to the same subnet

Topic

Describe:

子网掩码是用来判断任意两台计算机的IP地址是否属于同一子网络的根据。最为简单的理解就是两台计算机各自的IP地址与子网掩码进行AND运算后，如果得出的结果是相同的，则说明这两台计算机是处于同一个子网络上的，可以进行直接的通讯。就这么简单。

Take a look at the following example:
One of the operation demos:

IP地址:192.168.0.1子网掩码:255.255.255.0AND运算转化为二进制进行运算：IP地址:11010000.10101000.00000000.00000001 子网掩码:11111111.11111111.11111111.00000000 AND运算:11010000.10101000.00000000.00000000 转化为十进制后为： 192.168.0.0

The second of the Operation demo:

IP地址:192.168.0.254 子网掩码:255.255.255.0 AND运算转化为二进制进行运算：IP地址:11010000.10101000.00000000.11111110 子网掩码:11111111.11111111.11111111.00000000 AND运算:11010000.10101000.00000000.00000000 转化为十进制后为：192.168.0.0通过以上对两台计算机IP地址与子网掩码的AND运算后，我们可以看到它运算结果是一样的。均为192.168.0.0，所以这二台计算机可视为是同一子网络。

Interface description
Prototype:

int IsSameSubNetwork(char * pcIp1, char * pcIp2, char * pcSubNetworkMask);

Input parameters:

char * pcIP1: 计算机1的IP地址，格式：“192.168.0.254”char * pcIP2: 计算机2的IP地址，格式：“192.168.0.1”char * pcSubNetworkMask: 子网掩码，格式：“255.255.255.0”

return value:

0：IP1与IP2不属于同一子网络。1：IP1与IP2属于同一子网络。

Practice Stage:

Code

/* ---------------------------------------* Date: 2015-07-05* sjf0115* title: Determine whether the IP addresses of any two computers belong to the same subnet * Source: Huawei Machine Test exercises---- -------------------------------------*/#include <iostream>#include "OJ.h"#include <string>#include <vector>using namespace STD;/* Function: Determine the IP address of the two computers is the same subnet. Prototype: int issamesubnetwork (char * pcIp1, char * pcIp2, char * pcsubnetworkmask); input parameter: char * pcIP1: Computer 1 IP address, format: "192. 168.0.254 "; char * pcIP2: IP address of Computer 2, format:" 192.168.0.1 "; char * pcsubnetworkmask: Subnet mask, Format:" 255.255.255.0 "; return value: 0:ip1 And IP2 do not belong to the same sub-network; 1:ip1 and IP2 belong to the same subnet; *///Check that the subnet mask and IP format are correct and return fragmentationBOOLCheckip (stringStr vector<int>&numvec) {intSize = Str.size ();intPointcount =0;string:: Size_type index =0;intPrepoint =0; vector<string>Part while(Index = str.find_first_of ('. ', index))! =string:: NPOs) {//.. There are numbers between        if(Index > Prepoint)        {Part.push_back (Str.substr (prepoint,index-prepoint)); }//if++index;        Prepoint = index;    ++pointcount; }//while    if(Prepoint < size)    {Part.push_back (Str.substr (prepoint)); }//if    intPartsize = Part.size ();if(Partsize! =4){return false; }//if    //Judge that each part belongs to 0-255    intNum for(inti =0; i < partsize;++i) {num = Atoi (PART[I].C_STR ()); Numvec.push_back (num);if(Num <0|| num >255){return false; }//if}//for    //On behalf of the wrong IP    if(Pointcount! =3){return false; }//if    return true;}intIssamesubnetwork (Char* PCIP1,Char* PCIP2,Char* Pcsubnetworkmask) {if(PCIP1 = = NULL | | pcIp2 = = NULL | | pcsubnetworkmask = = NULL) {return 0; }//if    //Convert to String (own custom)    stringIP1 (PCIP1);stringIP2 (PCIP2);stringNET (pcsubnetworkmask); vector<int>Ip1vec; vector<int>Ip2vec; vector<int>Netvec;intRESULT,RESULT2;//IP subnet Mask input legal    if(Checkip (Ip1,ip1vec) && Checkip (Ip2,ip2vec) && Checkip (Net,netvec)) { for(inti =0; I <4; ++i) {result = Ip1vec[i] & Netvec[i]; RESULT2 = Ip2vec[i] & Netvec[i];if(Result! = RESULT2) {return 0; }//if}//for}//if    Else{return 0; }//else    return 1;}

Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.

[Huawei Machine Test exercises]54. Determine whether the IP addresses of any two computers belong to the same subnet