#include <stdio.h>
#include <stdlib.h>
#include <math.h>

float pressure_hpa;

int read_bmp280(float altitude) {
  FILE * fp;
  float station_pressure, sea_level_pressure;
  fp = fopen("/sys/bus/iio/devices/iio:device0/in_pressure_input", "r");
  fscanf(fp, "%f", &station_pressure);
  fclose(fp);
  sea_level_pressure = station_pressure / powf(1.0f - (altitude / 44330), 5.255f);
  printf("Sea level pressure: %.4f\n", sea_level_pressure);
  pressure_hpa = sea_level_pressure * 10;

  return 0;
}