test.cc

#include <iostream>
#include <sstream>
#include <iomanip>
#include <locale>

// Compile with: g++ -Wall --std=c++11 test.cc -o testing

using namespace std;

std::string FormatWithCommas(uint64_t value)
{
        stringstream ss;

        ss.imbue(locale(""));
        ss << fixed << value;
        return ss.str();
}

int main () {

    for (uint64_t i=1; i < 1000000000; i += 10^i) {
        cout << i << " : " << FormatWithCommas(i) << endl;
    }
    return 0;
}