fileIO

#include <iostream>
#include <fstream>

int main()
{
    std::ofstream outf;

    //std::ios::app - append to file
    //std::ios::ate - at the end - go to the end of file
    //std::ios::binary - open file in binary mode
    //std::ios::in - open file to read - input mode default for ifstream
    //std::ios::out - open file for writing - output mode default for ofstream
    //std::ios::trunc - delete file if exist

    outf.open("file.txt");
    if (!outf) { std::cout << "IO ERROR! cannot open file!\n"; return 1; };

    //outf << "Hello, from C++ file io app!\n";
    //outf << "One more line of text saved in file\n";
    //outf << "Last line! Thats all for now!\n";
    //int num{ 100500 };

    //for (int i{0}; i < 4; ++i)
    //{
    //  std::cout << (int)*((uint8_t*)(&num + i)) << '\n';
    //};

    float val{};
    for (int i{0}; i < 10; ++i)
    {
        val = ((float)i / (rand() % 100 + 1));

        std::cout << "Line number: ";
        std::cout << i << '\n';
        //<< val << '\n';
        outf << "Line number: ";
        outf << i << '\n';
        //' ' << val << '\n';
    }

    outf.close();

    std::fstream iof;
    iof.open("file.txt", std::ios::in | std::ios::out | std::ios::ate);
    if (!iof) { std::cout << "IO ERROR! cannot open file!\n"; return 1; };

    std::cout << "\nTry to read file content: \n";
    char buf[200];
    int numI{};
    float numF{};

    // seekg(pos, rel) - move read (get) position
    // seekp(pos. rel) - move write (put) position
    // tellg() - say read (get) position
    // tellp() - say write (put) position
    // REl
    // std::ios:beg
    // std::ios:end
    // std::ios:cur

    std::cout << "\nRead pos: " << iof.tellg() << "\nWrite pos: " << iof.tellp() << '\n';
    iof.seekp(-(iof.tellp()), std::ios::end);
    iof << "Some line of text! :)";
    iof.seekg(0, std::ios::beg);
    std::cout << "\nRead pos: " << iof.tellg() << "\nWrite pos: " << iof.tellp() << '\n';

    while (!iof.eof())
    {
        iof.getline(buf,200);
        std::cout << buf << '\n';
        //inf >> numI;
        //if (inf.fail()) break;
        //inf >> numF;
        //if (inf.fail()) break;
        //std::cout << buf << ' ';
        //std::cout << numI << ' ' << numF << '\n';
        //inf.ignore(100, '\n');
    }

    iof.close();

}