This function or variable may be unsafe

#define _CRT_SECURE_NO_WARNINGS

#include <iostream>
using std::cout;
using std::endl;
using std::cerr;
#include <cstdlib>
using std::exit;
#include <fstream>
using std::ifstream;
using std::ofstream;
#include <regex>
using std::regex;
using std::regex_replace;
#include <string>
using std::string;
 
int main()
{
    ifstream ifs("body.txt",ifstream::in);
    if(!ifs){cerr <<"don't open file"<<endl; exit(1);}
 
    string str;
    char c;
    while(ifs.get(c))str+=c;
    //str="<script> hellow world\nasdfsdf\rsdaf\t</script>";
    //cout <<str<<endl;
    str=regex_replace(str,regex("<script[^<>]*>(?:\n|\t|\r|.)*?</script>"),string("asdfsdf"));
    //cout <<str<<endl;
    cout <<"end"<<endl;
 
    return 0;
}

#include <iostream>
#include <string>
#include <regex>
 
 
 
int main()
{
    using namespace std;
 
    try
    {
        string TestString = "127.0.0.1";
        string RegexPattern = "([0-9]{1,3}\\.){3}[0-9]{1,3}";
        regex  StdRex(RegexPattern);
        cout << regex_match(TestString, StdRex) << endl;
    }
 
    catch (exception const &Exc)
    {
        cerr << "ERROR: " << Exc.what() << endl;
    }
 
    return 0;
}

#define _CRT_SECURE_NO_WARNINGS

#pragma once