An Exception That Carries a Code

1#include <iostream>
2#include <stdexcept>
3#include <string>
4 
5class HttpError : public std::runtime_error {
6    int m_status;
7public:
8    HttpError(int status, const std::string& text)
9        : std::runtime_error(text), m_status(status) {}
10    int status() const { return m_status; }
11};
12 
13void fetch(const std::string& page) {
14    if (page == "/secret") {
15        throw HttpError(403, "forbidden");
16    }
17    if (page == "/old") {
18        throw HttpError(404, "not found");
19    }
20    std::cout << "200 " << page << "\n";
21}
22 
23int main() {
24    std::string pages[] = {"/home", "/secret", "/old"};
25    for (const std::string& page : pages) {
26        try {
27            fetch(page);
28        } catch (const HttpError& e) {
29            std::cout << e.status() << " " << e.what() << "\n";
30        }
31    }
32    return 0;
33}