gistfile1.txt

#include <cmath>
#include <cstdio>
#include <fstream>
#include <iomanip>
#include <iostream>

#include <nonius/main.h++>

struct CRead
{
    CRead(char const* filename) : _filename(filename) {}

    void operator()()
    {
        FILE* file = fopen(_filename, "r");

        int count = 0;
        while (fscanf(file, "%s", _buffer) == 1) { ++count; }

        fclose(file);
    }

    char const* _filename;
    char _buffer[1024];
};

NONIUS_BENCHMARK("C", [](nonius::chronometer meter)
{
    CRead reader("big.txt");
    meter.measure([&]() { reader(); });
})

struct CppRead
{
    CppRead(char const* filename) : _filename(filename), _buffer() {}

    enum { BufferSize = 16184 };

    void operator()()
    {
        std::ifstream file(_filename, std::ifstream::in);

        // comment to remove extended buffer
        file.rdbuf()->pubsetbuf(_buffer, BufferSize);

        int count = 0;
        std::string s;
        while (file >> s) { ++count; }
    }

    char const* _filename;
    char _buffer[BufferSize];
};

NONIUS_BENCHMARK("C++", [](nonius::chronometer meter)
{
    CppRead reader("big.txt");
    bool oldSyncSetting = std::ios_base::sync_with_stdio(false);
    meter.measure([&]() { reader(); });
    std::ios_base::sync_with_stdio(oldSyncSetting);
})