#include <iostream>
#include <string>
 
using std::string;
 
int CTOI(char a)
{
   return a - 48;
}
 
char ITOC(int a)
{
   if (a == 0)
      return '0';
   return a + '0';
}
 
int creDec(int a, int b)
{
   return (a * 10) + b;
}
 
string divide2(string str)
{
   string ret;  // Object to be returned.
   int rem = 0; // Keep track of remainders.
 
   // Iterate over the characters of the input string.
   auto iter = str.begin();
   auto end = str.end();
   for ( ; iter != end; ++iter )
   {
      int n1 = CTOI(*iter);     // The number from the string.
      int n2 = creDec(rem, n1); // The number after we account for the remainder.
      int n3 = n2/2;            // Result of the division.
      rem = n2%2;               // Remainder of the division.
 
      if ( ret.empty() && n3 == 0 )
      {
         // Do nothing. There is no need to addd leading zeros to ret.
      }
      else
      {
         // Add the character corresponding to n3 to ret.
         ret.push_back(ITOC(n3));
      }
   }
 
   // If the return value is an empty string, return "0".
   if ( ret.empty() )
   {
      return "0";
   }
   else
   {
      return ret;
   }
}
 
void test(string const& in)
{
   std::cout << "Result of dividing " << in << " by 2 is: " << divide2(in) << std::endl;
}
 
int main()
{
   test("0");
   test("1");
   test("2");
   test("3");
   test("1183");
   test("000000000");
   test("36032092435013184350131843501318435013184350131843501318");
}
 

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