W dniu 04.07.2017 o 15:05, Borneq pisze:
> Tu znalazłem dobrze rozpisane:
> http://www.cs.trincoll.edu/~ram/cpsc110/inclass/conv
ersions.html
> może się przydać

Ostatecznie, trochę pozmieniałem kolejność w baseToNumber
Gotowiec:
#include <string>
#include <boost/multiprecision/cpp_int.hpp>

std::string numberToBase(boost::multiprecision::cpp_int n, int base)
{
const int max_buf = 128; //128 bit to binary
char buf[max_buf+1];
buf[max_buf] = 0;
int pos = max_buf - 1;
while (n != 0)
{
boost::multiprecision::cpp_int rb = n % base;
int r = (int)rb;
n = n / base;
char letter;
if (r < 10)
letter = '0' + r;
else
letter = 'a' + (r - 10);
buf[pos] = letter;
pos--;
}
return buf + pos + 1;
}

boost::multiprecision::cpp_int baseToNumber(std::string str, int base)
{
boost::multiprecision::cpp_int n = 0;
for (int i = 0; i< str.length(); i++)
{
char letter = tolower(str[i]);
int r;
if (letter >= '0' && letter <= '9')
r = letter - '0';
else
r = letter - 'a' + 10;
n = n * base + r;
}
return n;
}

int main()
{
std::string strnum = numberToBase(642452, 16);
std::cout << strnum << std::endl;
boost::multiprecision::cpp_int n = baseToNumber(strnum, 16);
std::cout << n << std::endl;
return 0;
}