#include <iostream>
#include <vector>
#include <stdexcept>

int main() {
    try {
        std::vector<int> vec{3, 4, 3, 1};
        int i{vec.at(4)}; // Throws an exception, std::out_of_range (indexing for vec is from 0-3 not 1-4)
    }
    // An exception handler, catches std::out_of_range, which is thrown by vec.at(4)
    catch (std::out_of_range &e) {
        std::cerr << "Accessing a non-existent element: " << e.what() << '\n';
    }
    // To catch any other standard library exceptions (they derive from std::exception)
    catch (std::exception &e) {
        std::cerr << "Exception thrown: " << e.what() << '\n';
    }
    // Catch any unrecognised exceptions (i.e. those which don't derive from std::exception)
    catch (...) {
        std::cerr << "Some fatal error\n";
    }
}