boost正则式解析MAC地址和IP地址

我所用的boost版本为：1.49.0

regex库需要提前编译好，并链接进来。如果你不想使用boost库，可以参考这篇，纯代码解析判断IP是否合法： http://www.cppblog.com/smagle/archive/2010/01/08/105184.html

#include <cstdlib>
#include <stdlib.h>
#include <boost/regex.hpp>
#include <string>
#include <iostream>
using namespace std;
using namespace boost;

void check_result(const string &expr, const string &str)
{
    regex expression(expr);
    cmatch what;

    cout<<str<<endl;

    if (regex_match(str.c_str(), what, expression))
    {
        for(int i = 1; i < what.size(); i++)
            cout<<"segment\t"<<what[i].str()<<endl;
    }
    else
    {
        cout<<"Invalid!"<<endl;
    }
    cout<<endl;
}

int main(int argc, char* argv[])
{
    string mac("12:34:af:1D:3D:5F");
    //string str = "([0-9a-fA-F]{2}:){5}([0-9a-fA-F]{2})"; //这种只会打印后两段
    string mac_fmt = "([0-9a-fA-F]{2}):([0-9a-fA-F]{2}):([0-9a-fA-F]{2})"
                     ":([0-9a-fA-F]{2}):([0-9a-fA-F]{2}):([0-9a-fA-F]{2})";
    check_result(mac_fmt, mac);

    string ip1 = "128.10.3.13";    //合法
    string ip2 = "255.10.3.13";    //不合法,leftmost法则，所以不能匹配第一段的最后一节
    string ip_fmt = "(25[0-4]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[1-9])"
        "."
        "(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9])"
        "."
        "(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9])"
        "."
        "(25[0-4]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[1-9])"; 

    check_result(ip_fmt, ip1);
    check_result(ip_fmt, ip2);

    return 0;
}