Sabiranje dva velika broja

// dragutinmarjanovic
#include <iostream>
using namespace std;

int sl_cr(char a)
{
    switch(a)
    {
             case '0': return 0; break;
             case '1': return 1; break;
             case '2': return 2; break;
             case '3': return 3; break;
             case '4': return 4; break;
             case '5': return 5; break;
             case '6': return 6; break;
             case '7': return 7; break;
             case '8': return 8; break;
             case '9': return 9; break;
    }
}

char cr_sl(int a)
{
    switch(a)
    {
             case 0: return '0'; break;
             case 1: return '1'; break;
             case 2: return '2'; break;
             case 3: return '3'; break;
             case 4: return '4'; break;
             case 5: return '5'; break;
             case 6: return '6'; break;
             case 7: return '7'; break;
             case 8: return '8'; break;
             case 9: return '9'; break;
    }
}

string saberi(string a, string b)
{
       int m=0, s=0;
       string k="";
       string t="";

       if (a.length()>b.length())
       {
          for (int i=0; i<a.length()-b.length(); i++)
              t = t + "0";
              t = t + b;
              b = t;
       }
       else if (b.length()>a.length())
       {
          for (int i=0; i<b.length()-a.length(); i++)
              t = t + "0";
              t = t + a;
              a = t;
       }

       for (int i=a.length()-1; i>=0; i--)
       {
           s = sl_cr(a[i]) + sl_cr(b[i]) + m;
           k = k + cr_sl(s%10);
           m = s/10;
       }

       if (m>0)
          k = k + cr_sl(m);

       return k;
}

main()
{
      string a, b;

      cin >> a >> b;

      string s = saberi(a, b);

      for (int i=s.length()-1; i>=0; i--)
          cout << s[i];

      cout << endl;

      system("PAUSE");
}