将bignum类型结构转换为人类可读字符串的有效方法是什么？

#include <iostream>
#include <string>
#include <iomanip>

bignum_num = 123456789012345678901234567890123456789012345678901234567890;
long long_num = std::stoll(bignum_num);

std::cout << "The big number: " << long_num << std::endl;

#include <iostream>
#include <string>
#include <iomanip>

int main() {
    bignum_num = 123456789012345678901234567890123456789012345678901234567890;
    long long_num = std::stoll(bignum_num);
    
    std::cout << "The big number: " << long_num << std::endl;
    
    return 0;
}