infoarena informatica de performanta

Am o problema, nu inteleg de ce imi sare in timpul compilarii peste instructiunea for.

codul:

#include <iostream>
#include <string.h>

using namespace std;

char sir[20];
int n;

void decodificare()
{
   int index = 0;
   char tablou[10][10];



   for (int i = 0; i < n; i++)
   {
      for (int j = 0; j < n; j++)
      {
         tablou[j] = sir[index];
         index++;

         cout << tablou[j] << " ";

      }
      cout << endl;
      if (index == n*n)
         break;
   }

   char cuvant[10];
   index = 0;
   int i = 0, j = n - 1;
   while (index <= n)
   {
      if (i == n - 1 && j == 0)
      {
         i = 0;
         while (i<n && j<n)
         {
            cuvant[index] = tablou;
            index++;
            i++;
         }
         break;
      }
      else
      {
         cuvant[index] = tablou[j];
         i++;
         j--;
         index++;
      }
   }

   cout << cuvant << endl;
}

int main()
{
   int n;
   cout << "n=";
   cin >> n;
   cout << "sir=";
   cin.get();
   cin.get(sir, 20);
   decodificare();
   system("pause");
    return 0;
}