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// srand test

//********************************************
// randomize functions
//********************************************

// global variables and functions to plant a random seed and to randomize
// how to use:
// srand(x)                     // x = val. for repet. sequences
// myVar = rand_() % 100;       // assignes a random number


unsigned long _RAND_SEED_ = 1;  //  patched by srand()
unsigned long  START_SEED = abs(CurrentTick()*BatteryLevel());


unsigned long rand_()           // random function
{
  _RAND_SEED_ = _RAND_SEED_ * 1103515245 + 12345;
  return (_RAND_SEED_ % (RAND_MAX + 1));
}



void srand(int seed)            // seeds for a new random series
{
  _RAND_SEED_ = seed;           // patch
}

task main(){
  int irVal;
  
  srand(START_SEED);
  irVal=rand_()%100;
  printf("randVal=%3d", irVal);
  while(1) {
    irVal=rand_()%100;
    printf("randVal=%3d", irVal);
    Wait(500);
  }
}

Code: Select all

// srand test

#define printf1( _x, _y, _format1, _value1) { \
  string sval1 = FormatNum(_format1, _value1); \
  TextOut(_x, _y, sval1); \
}


//********************************************
// randomize functions
//********************************************

// global variables and functions to plant a random seed and to randomize
// how to use:
// srand(x)                         // x = val. for repet. sequences
// myVar = rand_() % 100;           // assignes a random number


unsigned long _RAND_SEED_ = 1;      // 1= default value (program start)
unsigned long _OLD_SEED_  = 1;


unsigned long rand_()               // random function
{
  _RAND_SEED_ = _RAND_SEED_ * 1103515245 + 12345;
  return (_RAND_SEED_ % (RAND_MAX + 1));
}



void srand(unsigned long seed)      // seeds for a new random series
{

  if (seed==0)                      // 0: a "real" randomized random seed
    {seed = abs(CurrentTick()*BatteryLevel());}  // substitute to time(0)

  else
  if (seed==-1) {                   // -1: restore last random series
    seed = _OLD_SEED_;
  }

  _OLD_SEED_  = seed;
  _RAND_SEED_ = seed;               // patch for rand_ function
}



task main(){
  int irVal;
  
  printf1(0,56, "new1:%10d", _OLD_SEED_); // no srand: default=1
  irVal=rand_()%100;
  printf1( 0,48, "r1= %2d", irVal);
  irVal=rand_()%100;
  printf1(48,48, "r2= %2d", irVal);
  
  srand(0);                               // 0: real" randomized random seed
  printf1(0,40, "new0:%10d", _OLD_SEED_);
  irVal=rand_()%100;
  printf1( 0,32, "r1= %2d", irVal);
  irVal=rand_()%100;
  printf1(48,32, "r2= %2d", irVal);
  
  srand(-1);
  printf1(0,24, "-1re:%10d", _OLD_SEED_); // -1: again prev. random series
  irVal=rand_()%100;
  printf1( 0,16, "r1= %2d", irVal);
  irVal=rand_()%100;
  printf1(48,16, "r2= %2d", irVal);
  
  srand(0);
  printf1(0, 8, "new0:%10d", _OLD_SEED_); // 0: real" randomized random seed
  irVal=rand_()%100;
  printf1( 0, 0, "r1= %2d", irVal);
  irVal=rand_()%100;
  printf1(48, 0, "r2= %2d", irVal);
  

  while(1) {}

}