escape special chars C++

#include <iostream>
#include <fstream>
#include <unordered_map>
#include <string>
#include <chrono>
constexpr bool ADD_BENCHMARK_TO_LOG_FILE = true;

std::string GetMessageContent()
{
    if(auto file = std::ifstream("message.txt", std::ios::ate))
    {
        size_t size = file.tellg();
        file.seekg(0);
        std::string str(size, ' ');
        file.read(str.data(), size);
        return str;
    }
    else
    {
        std::cout << "Failed to get the message content.";
        std::exit(0);
    }
}
int main()
{
    const std::unordered_map<char, std::string> map
    {
        {'\\', "\\\\"}, {'`', "\\`"},
        {'*', "\\*"}, {'_', "\\_"}
    };
    const std::string content = GetMessageContent();

    auto t1 = std::chrono::high_resolution_clock::now();
    std::string result;
    result.reserve(content.size() * 1.5);
    for(const char c : content)
    {
        auto it = map.find(c);
        if(it != map.end())
            result += it->second;
        else
            result += c;
    }
    auto t2 = std::chrono::high_resolution_clock::now();
    auto time = std::chrono::duration_cast<std::chrono::nanoseconds>(t2 - t1).count();
    std::cout << "It took " << time << " nanoseconds";
    if constexpr(ADD_BENCHMARK_TO_LOG_FILE)
    {
        std::ofstream("log.txt", std::ios::app) << "C++: " << time << " nanoseconds.\n";
    }
    std::cin.get();
    std::cout << "See message content? Y or N\n";
    char c = std::cin.get();
    if(toupper(c) == 'Y')
    {
        std::cout << result << '\n';
    }
}