Integer Integer::operator-(const Integer& right) const //вычитание
{
if (sign > 0 && right.sign > 0)
if ((*this).abs() >= right.abs()) return (*this).minus(right);
else return -(right.minus(*this));
else if (sign > 0 && right.sign < 0)
return (*this) + (-right);
else if (sign < 0 && right.sign > 0)
return - ((-(*this)) + right);
else
if ((*this).abs() >= right.abs()) return -(*this).minus(right);
else return ((-right).minus(*this));
}
// Returns the Least Common Multiple of (*this) and n.
Integer Integer::lcm(const Integer& n) const
{
Integer a = n.abs();
Integer b = this->abs();
Integer g = this->gcd(n);
return a / g * b;
}
const DivisionResult Integer::doDivide(const Integer a, const Integer b) throw (DivideByZeroException) {
if (b.compareTo(Integer::ZERO) == 0) {
throw DivideByZeroException();
}
if (a.compareTo(Integer::ZERO) == 0) {
return DivisionResult(Integer::ZERO, Integer::ZERO);
}
if (b.compareTo(Integer::ONE) == 0) {
return DivisionResult(a, Integer::ZERO);
}
DivisionResult ret(Integer::ZERO, a.abs());
int lengthDifference = ret.remainder.bytes.length() - b.abs().bytes.length();
for (int i = lengthDifference; i >= 0; --i) {
std::stringstream ss;
ss << i;
Integer base = Integer::TEN.power(ss.str());
Integer temp = b.abs().multiply(base);
while (temp.compareTo(ret.remainder) <= 0) {
ret.remainder = ret.remainder.subtract(temp);
ret.result = ret.result.add(base);
}
}
if (a.isPositive() != b.isPositive()) {
ret.result = ret.result.negate();
if (b.isPositive()) {
ret.remainder = b.subtract(ret.remainder);
} else {
ret.remainder = b.add(ret.remainder);
}
} else {
if (!b.isPositive()) {
ret.remainder = ret.remainder.negate();
}
}
return ret;
}
const Integer Integer::add(const Integer a) const {
std::stack<int> first;
std::stack<int> second;
std::stack<int> val;
std::stack<int> one;
std::stack<int> temp;
std::string ret;
const int thisLength = this->bytes.length();
const int aLength = a.bytes.length();
const int longest = thisLength > aLength ? thisLength : aLength;
for (int i = 0; i < longest - 1; ++i) {
one.push(0);
}
one.push(1);
if (this->positive == a.positive) {
for (int i = longest; i > 0; --i) {
if (i <= thisLength) {
first.push(charToInt(this->bytes.at(thisLength - i)));
} else {
first.push(0);
}
if (i <= aLength) {
second.push(charToInt(a.bytes.at(aLength - i)));
} else {
second.push(0);
}
}
val = doAdd(first, second);
if (!val.empty() && val.top() != 1) {
val.pop();
}
ret.push_back(this->positive ? '+' : '-');
while (!val.empty()) {
ret.push_back(intToChar(val.top()));
val.pop();
}
} else {
if (this->abs().compareTo(a.abs()) == 0) {
return Integer::ZERO;
}
if (this->positive) {
for (int i = longest; i > 0; --i) {
if (i <= thisLength) {
first.push(ninesComp(charToInt(this->bytes.at(thisLength - i))));
} else {
first.push(9);
}
if (i <= aLength) {
second.push(charToInt(a.bytes.at(aLength - i)));
} else {
second.push(0);
}
}
} else {
for (int i = longest; i > 0; --i) {
if (i <= thisLength) {
first.push(charToInt(this->bytes.at(thisLength - i)));
} else {
first.push(0);
}
if (i <= aLength) {
second.push(ninesComp(charToInt(a.bytes.at(aLength - i))));
} else {
second.push(9);
}
}
}
val = doAdd(first, second);
if (!val.empty()) {
if (val.top() == 1) {
ret.push_back('-');
val.pop();
while (!val.empty()) {
temp.push(val.top());
val.pop();
}
val = doAdd(temp, one);
if (!val.empty()) {
val.pop();
}
while (!val.empty()) {
ret.push_back(intToChar(val.top()));
val.pop();
}
} else {
ret.push_back('+');
val.pop();
while (!val.empty()) {
ret.push_back(intToChar(ninesComp(val.top())));
val.pop();
}
}
}
}
return Integer(ret);
}
