regex_match crashes C++11 application

Question

I wrote a simple REGEX to simply validate an IPv4 address. Though I am a C programmer, I have a small bit of experience with OOP and C++.

#include <iostream>
#include <regex>
#include <string>       
#include <string.h>
using namespace std;

#define REJECT  0;
#define ACCEPT  1;

bool validIP(string ipaddr){
    regex e("\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}");
    return regex_match(ipaddr.begin(),ipaddr.end(),e);
}

int validate(string ipstring){//, char *filelist){
    if(!validIP(ipstring)){
        cerr << "Please Use a Valid IP Address" << endl;
        return REJECT;
    }else{
        cout << "Valid IP Address" << endl;
        return ACCEPT;
    }
    //will continue when correct
    char *ip=new char[ipstring.size()+1];
    ip[ipstring.size()]=0;
    memcpy(ip,ipstring.c_str(),ipstring.size());
}

int main(int argc, char **argv){    
    string test;
    cin >> test;
    validate(test);
    //cout << test;
}

Upon compiling with g++ file.cpp --std=c++11 and executing, I receive the following error message:

The input I sent was "this is a test" and this error occurs regardless of whether or not the input string is a valid IP.