bigint::bigvalue_t do_bigadd
(bigint::bigvalue_t v1, bigint::bigvalue_t v2){
//do_mult may pass in empty vectors as args
if(v1.size() == 0) v1.push_back(0);
if(v2.size() == 0) v2.push_back(0);
char carry = 0;
bigint::bigvalue_t v3;
bool done1 = false;
bool done2 = false;
for (size_t i = 0; ; ++i) {
char digit1, digit2;
if (i < v1.size()) { digit1 = v1[i]; }
else { digit1 = 0; done1 = true; }
if (i < v2.size()) { digit2 = v2[i]; }
else { digit2 = 0; done2 = true; }
if (done1 && done2) break;
char sum = digit1 + digit2 + carry;
v3.push_back (sum % 10);
carry = sum / 10;
}
if (carry != 0) v3.push_back (carry);
return v3;
}
bigint::bigvalue_t trim(bigint::bigvalue_t result) {
for(auto it = result.rbegin(); it != result.rend()
and *it == 0; ++it) {
result.pop_back();
}
if(result.empty()) result.push_back(0);
return result;
}