Undefined characters when reading the contents of a file without a new line at the end of the file

Question

File (settings.txt) for parsing:

FULLSCREEN=On
V_SYNC=On [no "\n" at the end of file]

In case there is no value ENTER "\ n":

MapKey= FULLSCREEN      MapValue= On
MapKey= V_SYNC  MapValue= Onřřřř

With ENTER "\ n" at the end of the file it is output correctly (without "řřřř"):

MapKey= FULLSCREEN      MapValue= On
MapKey= V_SYNC  MapValue= On

How to change the program to work without adding a new line at the end of the file? The code:

#include<iostream>
#include<fstream>
#include<sstream>
#include<vector>
#include<cstdint>
#include<memory>


int main()
{
    std::vector<std::pair<std::string, std::string>> container;
    std::ifstream containerFile("settings.txt", std::ifstream::binary);
    containerFile.seekg(0, containerFile.end);
    std::uint64_t fileSize = containerFile.tellg();
    containerFile.seekg(0);
    std::unique_ptr<char> fileBuffer(new char[fileSize]);
    containerFile.read(fileBuffer.get(), fileSize);

    std::istringstream fileContent(fileBuffer.get());
    std::string fileLine;
    while (std::getline(fileContent, fileLine))
    {
        std::istringstream bufferLine(fileLine);
        std::string option;
        if (std::getline(bufferLine, option, '='))
        {
            std::string value;
            if (std::getline(bufferLine, value))
            {
                container.emplace_back(make_pair(option, value));
            }
        }
    }
    for (auto &element : container)
    {
        std::cout << "MapKey= " << element.first << "   MapValue= " << element.second << std::endl;
    }
    containerFile.close();
}

Answer 1

You can rewrite your code this way:

std::vector<std::pair<std::string, std::string>> container;
std::ifstream containerFile("settings.txt");
containerFile.seekg(0, containerFile.end );
std::uint64_t fileSize = containerFile.tellg();
containerFile.seekg(0);

/* Changed code. Begin*/
containerFile >> std::noskipws;
std::vector<char> buffer;
buffer.reserve(fileSize);
std::copy(std::istream_iterator<char>(containerFile), std::istream_iterator<char>(), std::back_inserter(buffer));
buffer.push_back('\0');
std::istringstream fileContent(&buffer.front());
/* Changed code. End*/

std::string fileLine;
while (std::getline(fileContent, fileLine))
{
    std::istringstream bufferLine(fileLine);
    std::string option;
    if (std::getline(bufferLine, option, '='))
    {
        std::string value;
        if (std::getline(bufferLine, value))
        {
            container.emplace_back(make_pair(option, value));
        }
    }
}
for (auto &element : container)
{
    std::cout << "MapKey= " << element.first << "   MapValue= " << element.second << std::endl;
}
containerFile.close();

First of all, you should use the following flag: containerFile >> std::noskipws; This allows you to use spaces. Table spaces, carriage returns, and spaces are considered spaces in accordance with the documentation .

, buffer.push_back('\0'); '\ 0' .