Re: access violation question

On 27-12-2010 17:49, AnonMail2005@gmail.com wrote:


Here is the code, that will compile on Codeblocks (gcc compiler), but
leads to an error during execution.

I removed most comments (in Dutch), all ofstream (output to file) parts
(so some of the code must seem pointless now), and I englished some
variable names. I used an input function rather than arguments to
main(), so I could give some suggestions about the input values.
Comments on the miserable coding are welcome, but that's not MY first
concern at the moment.

--------------------------------------------------------------

#include <iostream>
#include <cstdlib>
#include <vector>
#include <algorithm>
#include <ctime>

using namespace std;

unsigned int n, hoogste = 0, trnsize, nr_rows, nr_trns,
              wissels, rounds;
double poolgem, pooltop, mutatiegraad;
typedef pair < vector<unsigned int>,unsigned int > paar;
vector<paar>vpool;
vector<pair <unsigned int,unsigned int> > vparen;

// rng used in random_shuffle()
class MyRandom // from Josuttis, p. 393-5
{
public:
     ptrdiff_t operator() (ptrdiff_t max)
     {
         double tmp;
         tmp = static_cast<double>(rand())
               / static_cast<double>(RAND_MAX);
         return static_cast<ptrdiff_t>(tmp * max);
     }
};
MyRandom rd;

inline bool groter (const paar& paar1, const paar& paar2)
{
     return paar1.second > paar2.second;
}

inline unsigned int terugtel (vector<unsigned int>& vint)
{
     unsigned int terugtel = 0, vangst = 0;
     while (terugtel != vint.size())
     {
         terugtel++;
         if (vint[terugtel] == terugtel + 1)
         {
             reverse (vint.begin(), vint.begin()+terugtel+1);
             terugtel = 0;
             ++vangst;
         }
     }
     return vangst;
}

inline unsigned int rvrs (vector<unsigned int> vint)
{
     unsigned int teller = 0;
     while (vint[0] != 1)
     {
         teller++;
         reverse (vint.begin(), vint.begin()+vint[0]);
     }
     return teller;
}

void toon_hoogste (const vector<unsigned int>& vi)
{
     cout << hoogste << " - ronde " << rounds << endl;
     vector<unsigned int> vidup(n);
     copy (vi.begin(), vi.end(), vidup.begin());
     unsigned int bijtellen = terugtel (vidup);
}

void toon_pooltop ()
{
     cout << "round " << rounds << ", average " << pooltop
          << endl;
}

double poolgemiddelde ()
{
     double pooltotaal = 0.0;
     for (unsigned int i = 0; i != nr_rows; ++i)
         pooltotaal += vpool[i].second;
     return pooltotaal / nr_rows;
}

void verwissel (const unsigned int index)
{
     unsigned int score, x, y, hulpwaarde;
     double klein;

     vector<paar> vtrn(trnsize);
     copy (vpool.begin()+index, vpool.begin()+index+trnsize,
           vtrn.begin());

     sort (vtrn.begin(), vtrn.end(), groter);

     vector<paar> vkand_trn;
     for (unsigned int deeln = 0; deeln != trnsize; ++deeln)
     {
         random_shuffle (vparen.begin(), vparen.end(), rd);
         vector<paar> vkand_ouder;
         for (unsigned int wisnr = 0; wisnr != wissels; ++wisnr)
         {
             vector<unsigned int> vtemp = vtrn[deeln].first;

             x = vparen[wisnr].first;
             y = vparen[wisnr].second;
             swap (vtemp[x], vtemp[y]);
             // if (x < vtemp.size() && y < vtemp.size())
             // swap (vtemp[x], vtemp[y]);

             score = rvrs(vtemp);
             if (score > hoogste)
             {
                 hoogste = score;
                 toon_hoogste (vtemp);
             }

             vkand_ouder.push_back(make_pair(vtemp,score));
         }

         sort (vkand_ouder.begin(), vkand_ouder.end(), groter);
         for (unsigned int i = 0; i != 2; ++i)
             vkand_trn.push_back(vkand_ouder[i]);
     }

     sort (vkand_trn.begin(), vkand_trn.end(), groter);
     copy (vkand_trn.begin(),
           vkand_trn.begin()+trnsize,
           vpool.begin()+index);
}

void initialiseer_pool()
{
     vector<unsigned int> row(n);
     nr_rows = nr_trns * trnsize;
     unsigned int score;
     for (unsigned int i = 0; i != n; ++i)
         row[i] = i+1;
     for (unsigned int i = 0; i != nr_rows; ++i)
     {
         do
         {
             random_shuffle (row.begin(), row.end(),rd);
         }
         while (row[0] == 1 || row[row[0]-1] == 1);

         score = rvrs(row);
         if (score > hoogste)
         {
             hoogste = score;
             toon_hoogste (row);
         }
         vpool.push_back(make_pair (row,score) );
     }
     poolgem = poolgemiddelde();
     if (poolgem > pooltop)
     {
         pooltop = poolgem;
         toon_pooltop();
     }
}

void gegevensinvoer()
{
     cout << "\n\nSettings like ...\n\n";
     cout << "n = 20\n";
     cout << "trnsize = 4\n";
     cout << "nr_trns = 100\n";
     cout << "prt = 15\n\n";
     cout << "... will cause the program to stop,\n";
     cout << "however the round in which this happens\n";
     cout << "may as well be round 0 as 200.\n\n";
     cout << "n (10-100): ";
     cin >> n;
     cout << endl << endl;
     cout << "trnsize (to be safe, choose 4): ";
     cin >> trnsize;
     cout << endl << endl;
     cout << "nr_trns (couple hundred): ";
     cin >> nr_trns;
     cout << endl << endl;
     unsigned int alle_wissels = n * (n-1) / 2;
     double prt;
     cout << "prt (a lowish percentage): ";
     cin >> prt;
     wissels = static_cast<unsigned int>(prt * alle_wissels / 100.0);
     cout << endl << endl;
}

int main()
{
     srand(time(0));
     gegevensinvoer();
     // initialize vparen
     for (int unsigned i = 0; i != n - 1; ++i)
         for (int unsigned j = i + 1; j != n; ++j)
         {
             pair<unsigned int,unsigned int> p (i,j);
             vparen.push_back(p);
         }
     rounds = 0;
     pooltop = 0.0;
     initialiseer_pool();

     while (true)
     {
         rounds++;
cout << '=' << rounds << "=\n";
         for (unsigned int i = 0; i != nr_trns; ++i)
             verwissel (i*trnsize);
         poolgem = poolgemiddelde();
         if (poolgem > pooltop)
         {
             pooltop = poolgem;
             toon_pooltop ();
         }
         for (unsigned int schud = 0; schud != nr_rows; ++schud)
             random_shuffle (vpool.begin(), vpool.end(),rd);
     }

     return 0;
}