Thread: How to use exception handling?

I have a code which gets public IP address and one segment of code causes crash if not connected to internet. So I'm trying to apply exception handling, but I don't really understand how it works in this case, can you help me?

Code:

#include <string.h>
#include <winsock2.h>
#include <windows.h>
#include <iostream>
#include <vector>
#include <locale>
#include <sstream>
using namespace std;
#pragma comment(lib,"ws2_32.lib")


string website_HTML;
locale local;
void get_Website(string url);
char lineBuffer[200][80] = { ' ' };
char buffer[10000];
char ip_address[16];
int i = 0, bufLen = 0, j = 0, lineCount = 0;
int lineIndex = 0, posIndex = 0;

//****************************************************

int main(void) {
    cout << "\n\n\n";
    try{
    get_Website("api.ipify.org");
    }
    catch (const char* error)
    {

    }
    for (size_t i = 0; i < website_HTML.length(); ++i) website_HTML[i] = tolower(website_HTML[i], local);

    istringstream ss(website_HTML);
    string stoken;

    while (getline(ss, stoken, '\n')) {

        //cout <<"-->"<< stoken.c_str() << '\n';

        strcpy_s(lineBuffer[lineIndex], stoken.c_str());
        int dot = 0;
        for (int ii = 0; ii < strlen(lineBuffer[lineIndex]); ii++) {

            if (lineBuffer[lineIndex][ii] == '.') dot++;
            if (dot >= 3) {
                dot = 0;
                strcpy_s(ip_address, lineBuffer[lineIndex]);
            }
        }

        lineIndex++;
    }
    cout << "Your IP Address is  " << ip_address << " \n\n";


    cout << "\nPress ANY key to close.\n\n";
    cin.ignore(); cin.get();

    return 0;
}

//****************************************************

void get_Website(string url) {
    WSADATA wsaData;
    SOCKET Socket;
    SOCKADDR_IN SockAddr;
    int lineCount = 0;
    int rowCount = 0;
    struct hostent *host;
    string get_http;


    get_http = "GET / HTTP/1.1\r\nHost: " + url + "\r\nConnection: close\r\n\r\n";

    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
        cout << "WSAStartup failed.\n";
        system("pause");
        //return 1;
    }

    Socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    host = gethostbyname(url.c_str());

    SockAddr.sin_port = htons(80);
    SockAddr.sin_family = AF_INET;
    SockAddr.sin_addr.s_addr = *((unsigned long*)host->h_addr);

    if (connect(Socket, (SOCKADDR*)(&SockAddr), sizeof(SockAddr)) != 0) {
        cout << "Could not connect";
        system("pause");
        //return 1;
    }
    send(Socket, get_http.c_str(), strlen(get_http.c_str()), 0);

    int nDataLength;
    while ((nDataLength = recv(Socket, buffer, 10000, 0)) > 0) {
        int i = 0;
        while (buffer[i] >= 32 || buffer[i] == '\n' || buffer[i] == '\r') {

            website_HTML += buffer[i];
            i += 1;
        }
    }

    closesocket(Socket);
    WSACleanup();

}

e.g.

Code:

#include <stdexcept>

void get_Website(const std::string& url)
{
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
        throw std::runtime_error("WSAStartup failed");
    }
}

int main()
{
    try {
        get_Website("api.ipify.org");
    } catch (const std::exception& e) {
        std::cerr << e.what() << std::endl;
    } catch (...) {
        std::cerr << "Unknown exception" << std::endl;
    }
}