A 32-bit XOR Shift LFSR (Linear Feedback Shift Register).

xor-shift-lfsr.cpp

unsigned int XORShiftLinearFeedbackShiftRegister(unsigned int state, unsigned int seed, int index) {
    /* A 32-bit XOR Shift LFSR.
     * The lower 16 bits can be used as a pseudo random number generator.
     * Based on the XORShift LFSR source code example at https://stackoverflow.com/questions/65661856/how-to-do-an-8-bit-16-bit-and-32-bit-linear-feedback-shift-register-prng-in-ja";
     * IMPORTANT: The seed must NEVER be zero, otherwise the LFSR will get stuck.
     */

    unsigned int lfsr = index == 0 ? seed : state;
    lfsr ^= (lfsr & 0x0007ffff) << 13;
    lfsr ^= lfsr >> 17;
    lfsr ^= (lfsr & 0x07ffffff) << 5;
    return lfsr;
}

// An example that generates 21 pseudo-random numbers.
// The number sequence is always the same; hence pseudo-random.
// Change the seed to change the starting point of the sequence.
int main() {
  unsigned int state = 0;
  unsigned int seed = 4294967295; // I simply asked Llama to generate a random unsigned int; NOTE: Must not be zero.
    
  for(int i = 0; i < 20; i++) {
    state = XORShiftLinearFeedbackShiftRegister(state, seed, i);
    printf("%d\n", state);
  }
}