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C-/C++-Quelltext

unsigned mersenne_twister(void) {
  const int N = 624;
  const int M = 397;
  const unsigned A[2] = { 0, 0x9908b0df };
  const unsigned HI = 0x80000000;
  const unsigned LO = 0x7fffffff;

  static unsigned y[N];
  static int index = N+1;

  if (index >= N) {
    if (index > N) {
       // initialisiere y mit Pseudozufallszahlen:
       unsigned r = 9, s = 3402;
       for (int i=0 ; i<N ; ++i) {
          r = 509845221 * r + 3;
          s *= s + 1;
          y[i] = s + (r >> 10);
       }
    }
    unsigned h;
    for (int k=0 ; k<N-M ; ++k) {
       h = (y[k] & HI) | (y[k+1] & LO);
       y[k] = y[k+M] ^ (h >> 1) ^ A[h & 1];
    }
    for (int k=N-M ; k<N-1 ; ++k) {
       h = (y[k] & HI) | (y[k+1] & LO);
       y[k] = y[k+(M-N)] ^ (h >> 1) ^ A[h & 1];
    }
    h = (y[N-1] & HI) | (y[0] & LO);
    y[N-1] = y[M-1] ^ (h >> 1) ^ A[h & 1];
    index = 0;
  }

  unsigned e = y[index++];
  // tempering:
  e ^= (e >> 11);
  e ^= (e << 7) & 0x9d2c5680;
  e ^= (e << 15) & 0xefc60000;
  e ^= (e >> 18);
  return e;
}