c++ base36 encoding example

base36.cpp

#include <cstdio>

#include <string>
#include <cstdint>
#include <cmath>
#include <algorithm>

#include <climits>
#include <cstdlib>

char seq[] = "0123456789abcdefghijklmnopqrstuvwxyz";


std::string base36_encode(uint64_t in){
    std::string result;

    while (in != 0) {
        result.push_back(seq[in % 36]);
        in /= 36;
    }

    std::reverse(result.begin(), result.end());
    return result;
}


int main(void) {

    uint64_t in = ULLONG_MAX;
    //uint64_t in = 9223372036854775807;

    std::string r = base36_encode(in);
    printf("%s\n", r.c_str());

    char* end = nullptr;
    uint64_t d = std::strtoull(r.c_str(), &end, 36);

    printf("%llu\n", d);

    return 0;
}