//string
big_integer::big_integer(std::string const& str) {
if (str == "" || str == "0") {
*this = big_integer();
}
else {
std::string temp = str;
int cut = 0;
if (temp.at(0) == '-')
cut = 1;
while (temp.at(cut) == '0' && cut < temp.size() - 1)
temp.erase(cut, cut);
if (temp == "0" || temp == "-0" || temp == "") {
*this = big_integer();
return;
}
std::reverse(temp.begin(), temp.end());
for (int i = 0; i < temp.size() - 1; ++i) {
if (!isdigit(temp[i])) {
throw parse_exception("Illegal character");
}
this->digits.push_back(temp[i] - 48);
}
if (temp[temp.size() - 1] == '-') {
sign = -1;
}
else {
sign = 1;
this->digits.push_back(temp[temp.size() - 1] - 48);
}
}
};
big_integer& big_integer::operator/=(big_integer const& rhs)
{
if (*this < rhs)
{
*this = big_integer(0);
return *this;
}
big_integer m(1);
big_integer a(-1), b(*this + 1);
while (b - a > big_integer(1))
{
m = div2(b + a + big_integer(1));
big_integer bb = m * rhs;
if (bb > *this) {
b = m;
}
else
{
a = m;
}
}
if (a * rhs <= *this) {
*this = a;
} else {
*this = b;
}
while (!data[data.size() - 1] and data.size() != 1) data.pop_back();
return *this;
}
std::string to_string(big_integer const& a)
{
std::string res = "";
big_integer aa (a);
big_integer bb (0);
big_integer cc (0);
big_integer dd (0);
if (a.flag == 1) {
aa.flag = false;
}
if (a == big_integer(0)) return "0";
while ((aa) > big_integer(0))
{
bb = aa / big_integer(1000000000);
cc = bb * big_integer(1000000000);
dd = aa - cc;
aa = bb;
for (int i = 0; i < 9; i++)
{
res += dd.data[0] % 10 + 48;
dd.data[0] /= 10;
}
}
while (res[res.size() - 1] == '0') res.pop_back();
if (a.flag == 1) {
res+='-';
}
for (int i = 0; i < res.size()/2; ++i)
{
std::swap(res[i], res[res.size()-1-i]);
}
return res;
}
big_integer::big_integer(std::string str)
{
if (str[0] == '-') flag = true; else flag = false;
for (int i = 0; i < str.size(); ++i)
{
*this *= big_integer(10);
*this += big_integer(str[i] - 48);
}
}
//subtract
big_integer& big_integer::operator-=(big_integer const& rhs) {
if (sign == rhs.sign) {
big_integer temp;
switch (absolute_comparator(*this, rhs)) {
case 0:
*this = big_integer();
return *this;
case 1:
break;
case -1:
temp = rhs - *this;
temp.sign = -temp.sign;
*this = temp;
return *this;
default:
break;
}
int carry = 0;
for (int i = 0; i < rhs.digits.size() || carry; ++i) {
digits[i] -= carry + (i < rhs.digits.size() ? rhs.digits[i] : 0);
carry = digits[i] < 0;
if (carry) digits[i] += 10;
}
while (digits.size() > 1 && digits.back() == 0)
digits.pop_back();
return *this;
}
else {
*this += -rhs;
return *this;
}
};
//add
big_integer& big_integer::operator+=(big_integer const& rhs) {
if (sign == 0) {
*this = rhs;
return *this;
}
if (rhs.sign == 0)
return *this;
if (sign == rhs.sign) {
int carry = 0;
for (int i = 0; i < std::max(digits.size(), rhs.digits.size()) || carry; ++i) {
if (i == digits.size())
digits.push_back(0);
digits[i] += carry + (i < rhs.digits.size() ? rhs.digits[i] : 0);
carry = digits[i] >= 10;
if (carry) digits[i] -= 10;
}
return *this;
}
else {
big_integer temp;
switch (absolute_comparator(*this, rhs)) {
case 0:
*this = big_integer();
return *this;
case 1:
if (sign == 1) {
*this -= -rhs;
}
else {
sign = 1;
*this -= rhs;
sign = -1;
}
return *this;
case -1:
sign = -sign;
temp = rhs - *this;
*this = temp;
return *this;
default:
break;
}
return *this;
}
};
