Question

I have a BigInt class I created that works correctly. I would like to add a constructor

BigInt(string s, int base)

that creates a BigInt operating in the given base. The newly extended class should work with any base between 2 and 36, using the digits 0, 1, …, 9, A, B, C, …, Z. How do I do this from what I have? (you may add new data members and such of course)

#include <string>
#include <vector>

class BigInt {
private:
   std::string m_String = "";
  
public:
   BigInt(std::string s)   // convert string to BigInt
   {
      for(int i = s.length() - 1; i >= 0; i--) {
        m_BigInt.push_back((int)s[i] - 48);
      }
   }

   std::string to_string() // get string representation
   {
       m_String = ""; // clear before print
       for (auto it = m_BigInt.rbegin(); it != m_BigInt.rend(); it++)
       {
           m_String += std::to_string(*it);
       }
       return m_String;
   }

   void add(BigInt b) // add another BigInt to this one with carry function
   {
       for (int digit = 0; digit != b.getVect().size(); digit++)
       {
      int temp = m_BigInt[digit] + b.getVect()[digit];
           if(temp >= 10) {
        if(digit + 1 != m_BigInt.size()) {
          m_BigInt[digit] = temp % 10;
          m_BigInt[digit + 1] = m_BigInt[digit + 1] + temp / 10;
        } else {
          m_BigInt[digit] = temp % 10;
          m_BigInt.push_back(temp / 10);
        }
      } else
        m_BigInt[digit] = temp;
     }
   }

   std::vector<int> getVect() // get BigInt vector
   {
       return m_BigInt;
   }
};

Answer 1

Program Code Screenshot

Program Sample Input/Output Screenshot

Program Code to Copy

#include <string>
#include <vector>
#include <iostream>

class BigInt
{
private:
   std::string m_String = "";
   std::vector<int> m_BigInt;
   int base;

public:
   BigInt(std::string s) // convert string to BigInt
   {
      for (int i = s.length() - 1; i >= 0; i--)
      {
         m_BigInt.push_back((int)s[i] - 48);
      }
      base = 10;
   }

   BigInt(std::string s, int base)
   {
      for (int i = s.length() - 1; i >= 0; i--)
      {
         // handle base above 10
         if (s[i] >= 'A' && s[i] <= 'Z')
         {
            m_BigInt.push_back(s[i] - 'A' + 10); //character A is 10
         }
         else
         {
            m_BigInt.push_back((int)s[i] - 48);
         }
      }
      this->base = base;
   }

   std::string to_string() // get string representation
   {
      m_String = ""; // clear before print
      for (auto it = m_BigInt.rbegin(); it != m_BigInt.rend(); it++)
      {
         // handle base above 10
         if (*it >= 10)
         {
            m_String += char(*it - 10 + 'A');
         }
         else
         {
            m_String += std::to_string(*it);
         }
      }
      return m_String;
   }

   void add(BigInt b) // add another BigInt to this one with carry function
   {
      for (int digit = 0; digit != b.getVect().size(); digit++)
      {
         int temp = m_BigInt[digit] + b.getVect()[digit];
         if (temp >= base)
         {
            if (digit + 1 != m_BigInt.size())
            {
               m_BigInt[digit] = temp % base;
               m_BigInt[digit + 1] = m_BigInt[digit + 1] + temp / base;
            }
            else
            {
               m_BigInt[digit] = temp % base;
               m_BigInt.push_back(temp / base);
            }
         }
         else
            m_BigInt[digit] = temp;
      }
   }

   std::vector<int> getVect() // get BigInt vector
   {
      return m_BigInt;
   }
};

// demo for changes
int main()
{
   BigInt a1("1101", 2);
   BigInt b1("1101", 2);
   a1.add(b1);
   std::cout <<"1101 (base 2) + 1111  (base 2) = "<< a1.to_string() << std::endl;

   BigInt a2("A20", 16);
   BigInt b2("13F", 16);
   a2.add(b2);
   std::cout <<"A20 (base 16) + 13F  (base 16) = "<< a2.to_string() << std::endl;
}