big int in cpp code example

Example 1: bigint c++

//bigint.cpp methods implementation
#include <stdexcept>
#include"Bigint.hpp"
#include<algorithm>
// CONSTRUCTOR OVERLOAD 
Bigint::Bigint(std::list<unsigned char>B) 
   :m_digits(B){}
Bigint::~Bigint(){}
//##################################### is_zero #########>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Amir Ammar
bool Bigint::is_zero()const
{
     if(m_digits.front()=='0'){
       return true;
     }
     return false;
}
//##################################### is_negative #########################################################
bool Bigint::is_negative() const{
   if(m_is_negative == true){
     return  true ;
   }else 
     return false;
}
//<<<<<<<<<<<<<<<<<<<<<<<<<<<insertion operator overloading<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< Amir Ammar
std::ostream& operator<<(std::ostream& out, const Bigint& i){
  for(auto b = i.m_digits.begin(); b != i.m_digits.end(); ++b){
    out<<(*b);
  }
  return (out);
}
//>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>extraction operator overloading>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Efi Fogel
std::istream& operator>>(std::istream& in, Bigint& i) {
  char c;
  in.get(c);
  if (c == '-') i.m_is_negative = true;
  else {
    if (! std::isdigit(c)) throw std::runtime_error("Invalid input");
    i.m_digits.emplace_front(c);
  }
  while (in.get(c) && (c != 0xa)) {
    if (! std::isdigit(c)) throw std::runtime_error("Invalid input");
    i.m_digits.emplace_front(c);
  }
  i.m_digits.reverse(); // additional method to return the reversed value (the real input)
  while(i.m_digits.front()=='0'&&i.m_digits.size()!= 1){ // while loop to earse additional zeroes 
    i.m_digits.pop_front();
    if(i.m_digits.size()== 1)
      break;
  }
  return in;
}

Example 2: bigint c++

//+++++++++++++++++++++++++++    overloaded pluse operator    ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// ++++++++++++++++++++++++++++        Amir Ammar             +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Bigint operator+(const Bigint& a, const Bigint& b){
  Bigint temp1 = a;
  Bigint temp2 = b;
  Bigint temp3;
  if(temp1.is_zero()&&temp2.is_zero()){temp3.m_digits={'0'};return temp3;}
  if(!temp1.is_negative() &&temp2.is_negative()){  // if  (+temp1) (+) (-temp2)  done 
    temp2.m_is_negative = false;
    temp3 = temp1-temp2;
    return temp3;
  }
  if(temp1.is_negative()&&!temp2.is_negative()){ // if  (-temp1) (+)  (+temp2)   done 
    temp1.m_is_negative = false;
    temp3 = temp2-temp1;
    return temp3;
  }
  int carry {0}; int sum{0};auto it1 = temp1.m_digits.rbegin(); auto it2 = temp2.m_digits.rbegin();
  while(it1 != temp1.m_digits.rend() && it2 != temp2.m_digits.rend() ){
    ((a.m_digits.size()>b.m_digits.size()))?temp2.m_digits.push_front('0'):temp1.m_digits.push_front('0');
    sum=((*it1-'0')+(*it2-'0')+carry);
    temp3.m_digits.emplace_front(sum%10+'0');
    carry=sum/10;
    ++it1; ++it2;
  }
  if(carry != 0)temp3.m_digits.emplace_front(carry+'0');
  if(temp1.is_negative()&&temp2.is_negative()) // if (-temp1) + (-temp2) done
  { 
    temp3.m_digits.emplace_front('-'); // we push eventually (-)
  }
  return temp3;
}
//-------------------------------- overloaded  minus operator ---------------------------------------- 
//--------------------------------------   Amir Ammar   ----------------------------------------
Bigint operator-(const Bigint& a,const Bigint& b)
{ 
  Bigint temp1(a);
  Bigint temp2(b);
  Bigint sub;
  if(temp1.is_zero()&&temp2.is_zero()){sub.m_digits={'0'};return sub;}
  if(!temp1.is_negative()&& temp2.is_negative()){  // (+temp1) - (-temp2) 
     temp2.m_is_negative = false;
     return temp1+temp2;    
  }
  if(temp1.is_negative() && !temp2.is_negative()){  // (-temp1) - (+temp2) 
     temp2.m_is_negative = true;
     return temp1+temp2;    
  }
  if(temp1.is_negative()&&temp2.is_negative()){
    temp1.m_is_negative = false;
    temp2.m_is_negative = false;
    return temp2 - temp1 ;
  }
  auto it_1 = temp1.m_digits.end(); 
  auto it_2 = temp2.m_digits.end(); 
  int one_less{0};
  int length = temp1.m_digits.size()-temp2.m_digits.size();
  if(length <0){
    for(int i = length ; i<0; ++i) // 
    ((temp1.m_digits.size()>temp2.m_digits.size())?temp2.m_digits.emplace_front('0'):temp1.m_digits.emplace_front('0'));
  }else
  {
    for(int i = length; i>0; --i)
      ((temp1.m_digits.size()>temp2.m_digits.size())?temp2.m_digits.emplace_front('0'):temp1.m_digits.emplace_front('0'));
  }
  auto it1 = temp1.m_digits.end(); auto it2 = temp2.m_digits.end();
  while(it1 != temp1.m_digits.begin() && it2 != temp2.m_digits.begin()){
      --it1; --it2; 
      int it1_int = *it1%48;
      int it2_int = *it2%48;
    if(it1_int-it2_int-one_less<0){
      it1_int+= 10;
      sub.m_digits.emplace_front(it1_int-it2_int-one_less+'0');
      one_less = 1;
    }else{
      sub.m_digits.emplace_front(it1_int-it2_int-one_less+'0');
      one_less = 0;
    }
  }
  if(one_less==1){
    sub=temp2-temp1 ;
    sub.m_digits.emplace_front('-');
  }
  while(sub.m_digits.front()=='0'&&sub.m_digits.size()!= 1){
    sub.m_digits.pop_front();
    if(sub.m_digits.size()== 1)
      break;
  }
  return sub.m_digits;
}