double thr double currentX startX currentY startY double result int ma

double thr() {

  double currentX = startX, currentY = startY;
  double result = 0;

  int i = 0, max = global_steps_counter;

  while (i < max) {
    result += pow(M_E, currentX) * sin(currentY);
  
    currentX += x_step;

    if (currentX > x_end) {
      currentX = x_begin;
      
      currentY += y_step;
      if (currentY > y_step) {
        // err?
      }    
    }

  i++;
}