Convert Number to String Without Convenience Methods

NumToString.cpp

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

class NumToString
{
private:
  struct Comparator
  {
    bool operator()(int x, int y) const
    {
      return x < y;
    }
  };

public:
  map<int, string, Comparator> nums;

  NumToString()
  {
    map[0] = "0";
    map[1] = "1";
    map[2] = "2";
    map[3] = "3";
    map[4] = "4";
    map[5] = "5";
    map[6] = "6";
    map[7] = "7";
    map[8] = "8";
    map[9] = "9";
  }

};

int main()
{
  int number = 1231241;
  NumToString numToString();
  string str;

  while (number != 0) {
    int remainder = number % 10;
    str.insert(0, NumToString.nums[number]);
    number -= remainder;
  }

  cout << str;
}