[LAB 4] Sum of prime numbers (Use Boolean Function)

void setup()
{
  size(500,500);
}

int countNumber = 0;
int maxNumber = 56;
int primeNumber = countNumber;
int count =0;
int sumNumber = 0;
void draw()
{
  background(0);
  while(primeNumber <= maxNumber)
  {
  if(check_primeNumber(primeNumber))
    {
      sumNumber += primeNumber;
    }
      primeNumber++;
  }
  textSize(25);
  text(countNumber,width/4,height/4);
  text(maxNumber,width/4,3*(height/4));
  textSize(60);
  text(sumNumber,3*(width/5),height/2);
}

boolean check_primeNumber(int maxNumber)
{
  int start = 2;
  while(start <= maxNumber)
    {
      if(start == maxNumber)
      {
        return true;
      }
      if(maxNumber%start == 0)
      {
        return false;
      }
      start++;
    }
    return false;
}