JAVASCRIPT

how to generate random number without using random function

unsigned short lfsr = 0xACE1u;
  unsigned bit;

  unsigned rand()
  {
    bit  = ((lfsr >> 0) ^ (lfsr >> 2) ^ (lfsr >> 3) ^ (lfsr >> 5) ) & 1;
    return lfsr =  (lfsr >> 1) | (bit << 15);
  }

random number without rand function

/** * Implementation of XorShift * algorithm in JavaScript */
var seed;

function xorShift(){

  seed ^= seed << 13;

  seed ^= seed >> 17;

  seed ^= seed << 5;

  return seed;
}