B4R Code Snippet Random number between X and Y

tchart · Aug 26, 2020

There are many code snippets on the forum for random numbers. This example is for a project Im doing that needs to randomly select 1 of 4 LED's. Im not too worried that its pseduo random but this code will get you a random number between 1 and 4 (but makes sure you dont get the same number twice in a row).

NOTE the upper limit is exclusive so for random numbers beween 1 and 4 we use 1 & 5. If you wanted a number between 2 and 6 you'd use 2 & 7.


Dim rNumber As Byte = 0
RunNative("getRandomNoDuplicate", Null)
Log("rNumber = ", rNumber)


#if C
int prevValue = -1;
int lower = 1;
int upper = 5; 

void getRandomNoDuplicate(B4R::Object* o)
{
  static int offset = 0;
  int randNumber = random(lower, upper);
  if (prevValue == randNumber)
  {
    offset++;
    if (offset >= upper - lower) offset = 1;
    randNumber += offset;
    if (randNumber >= upper) randNumber = lower + randNumber - upper;
  }
  prevValue = randNumber;
  b4r_main::_rnumber  = randNumber;
}
#End If

B4R Code Snippet Random number between X and Y

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