Function Help

Hi Everyone,
So, I had posted before about help with my sketch, although now I have cleaned it up a bit and need some help again. This time I am wondering how to create/call the frequency function correctly. The original code is from: Page has moved

What I wrote is below, although I am not getting any results. The problem, most likely, is that I am not actually getting the frequency to read.

#include <FreqCounter.h>

void setup()  {
  Serial.println ("");

void loop()  {
  Serial.print("Frequency: ");
  Serial.println(" Hz");
  Serial.print("Pressure: ");
  Serial.println(" PSI");

double Frequency()  {
  long int frq;
  FreqCounter::f_comp = 8;
  while (FreqCounter::f_ready == 0);
  {/*Do Nothing*/}
  return frq;

double Pressure()  {
  double frq = Frequency();
  double A = -4.170459900908042e-11;
  double B = -0.04637910393309745;
  double C = 1765.6201656883327;
  double Press = ((A*frq*frq)+(B*frq)+C);
  return Press;

void printFreq (void)  {
  double freq = Frequency();

void printPress(void)  {
  double Press = Pressure();

Did you try the example program on that page?

Did you try the example program on that page?

Yes I did, although when I copy that sketch into another sketch (datalogging sketch) that is reading a sensor from A0, the frequency counter doesn't work. So I was hoping by calling this as a function I might be able to figure something out.