gistfile1.cpp

#include <vector>
#include <string>
#include <iostream>
using namespace std;

class BigNumber
{
private:
  vector<int> v;
  
  vector<int> Add(vector<int>& A, vector<int>& B)
  {
    vector<int> copy(A);

    int i, t = 0;
    for (i = 1; i <= copy[0] || i <= B[0] || t; i++, t /= 10)
      copy[i] = (t += copy[i] + B[i]) % 10;
    copy[0] = i - 1;

    return copy;
  }
  
  vector<int> Multiply(vector<int>& A, int B)
  {
    vector<int> copy(A);

    int i, t = 0;
    for (i = 1; i <= copy[0] || t; i++, t /= 10)
      copy[i] = (t += copy[i] * B) % 10;
    copy [0] = i - 1;

    return copy;
  }

  vector<int> Multiply(vector<int>& A, vector<int>& B)
  {
    int i, j, t;
    vector<int> C(A[0] * B[0] + 1);

    for (i = 1; i <= A[0]; i++)
      {
	for (t=0, j=1; j <= B[0] || t; j++, t/=10)
	  C[i+j-1]=(t+=C[i+j-1]+A[i]*B[j])%10;
	if (i + j - 2 > C[0]) C[0] = i + j - 2;
      }
    
    return C;
  }
  
  vector<int> Subtract(vector<int> &A, vector<int> &B)
  {
    vector <int> copy(A);

    int i, t = 0;
    for (i = 1; i <= copy[0]; i++) {
      copy[i] -= ((i <= B[0]) ? B[i] : 0) + t;
      copy[i] += (t = copy[i] < 0) * 10;
    }
    for (; copy[0] > 1 && !copy[copy[0]]; copy[0]--);
    
    return copy;
  }

  vector<int> Divide(vector<int> &A, int B)
  {
    vector <int> copy(A);

    int i, t = 0;
    for (i = copy[0]; i > 0; i--, t %= B)
      copy[i] = (t = t * 10 + copy[i]) / B;
    for (; copy[0] > 1 && !copy[copy[0]]; copy[0]--);
   
    return copy;
  }
  
  int Reminder(vector<int> A, int B)
  {
    int i, t = 0;
    for (i = A[0]; i > 0; i--)
      t = (t * 10 + A[i]) % B;
    return t;
  }

  int cifre (int n)
  {
    int counter = 0;
    while (n != 0)
      {
	++counter;
	n /= 10;
      }
    return counter;
  }

public:
  BigNumber (string str)
  {
    v.push_back(str.size());
    for (auto i = str.rbegin(); i != str.rend(); ++i)
      v.push_back(*i - '0');
  }

  BigNumber (int n)
  {
    int size = cifre(n);
    
    if (size == 0)
      v.push_back(1);
    v.push_back (size);

    while (n != 0)
      {
	v.push_back(n % 10);
	n /= 10;
      }
  }

  BigNumber (const vector<int> &n, bool reversed = true)
  {
    if (reversed == true)
	for (int i = 0; i <= n[0]; i++)
	  v.push_back(n[i]);
    else
      {
	int size = n.size();
	v.push_back(size);
	for (auto i = n.rbegin(); i != n.rend(); ++i)
	  v.push_back(*i);
      }
  }

  BigNumber (const BigNumber& other)
  {
    for (int i = 0; i <= other.v[0]; ++i)
      v.push_back(other.v[i]);
  }

  BigNumber operator= (const BigNumber& other)
  {
    for (int i = 0; i <= other.v[0]; ++i)
      v.push_back(other.v[i]);
    return *this;
  }

  BigNumber operator+ (BigNumber other)
  {
    return Add(v, other.v);
  }

  BigNumber operator- (BigNumber other)
  {
    return Subtract(v, other.v);
  }

  BigNumber operator* (int n)
  {
    vector<int> answer = Multiply(v, n);
    BigNumber result(answer);
    return result;
  }

  BigNumber operator* (BigNumber other)
  {
    vector<int> answer = Multiply(v, other.v);
    BigNumber result(answer);
    return result;  
  }

  BigNumber operator/ (int n)
  {
    return Divide (v, n);
  }

  BigNumber operator% (int m)
  {
    return Reminder(v, m);
  }

  bool operator== (const BigNumber& other)
  {
    if (v[0] != other.v[0])
      return false;
    
    bool equal = true;
    for (unsigned int i = 0; i < (unsigned int)v[0]; ++i)
      if (v[i] != other.v[i])
	{
	  equal = false;
	  break;
	}

    return equal;
  }

  bool operator!= (const BigNumber& other)
  {
    return !operator==(other);
  }

  bool operator< (const BigNumber& other)
  {
    if (v[0] < other.v[0])
      return true;
    
    bool lesser = true;
    for (int i = 0; i < v[0]; ++i)
      if (v[i] > other.v[i])
	{
	  lesser = false;
	  break;
	}

    return lesser;
  }

  bool operator> (const BigNumber& other)
  {
    return !operator<(other);
  }

  friend ostream& operator<<(ostream& out, const BigNumber& item);
};

ostream& operator<< (ostream& out, const BigNumber& item)
{
  int size = item.v[0];
  for(int i = size; i > 0; --i)
    out << item.v[i];
  return out;
}

int main()
{
  
  BigNumber base = 4;
  BigNumber exp = 13;
  BigNumber zero = 0;
  
  //BigNumber answ = Math::RiseToPower(base, exp);
  
  BigNumber cinci(5);
  //BigNumber answ = ((cinci * exp) * (cinci + zero));
  BigNumber answ1 = ((base * exp) * (cinci * exp)); // works
	cout << "answ1: " << answ1 << endl;

  BigNumber answ2 = ((base * exp) * (cinci + exp)); // doesn't work
	cout << "answ2: " << answ2 << endl;
}