C/C++ :: Flow Meter - Count Certain Quantity Of Fluid Then Light Up Corresponding LED

I am attempting to write some code for a flow meter and LEDs using my Arduino. I need the flow meter to count a certain quantity of fluid, then light up an LED which corresponds to that quantity. I found this code on the internet and it was exactly what I needed but when I opened up the serial monitor to see if it worked it didn't. I have finally fixed the issue with it not counting anything at all, but it is still acting as if it was measuring the rate. how it counts and keeps track of how much fluid in total has passed through the flow meter ?

volatile int NbTopsFan; //variable to accumulate the number of pulses
float Calc = 0; //the volume flowed since measurement started, liters
void pulse() //This is the function that the interupt calls
int hallsensor = 2; //The pin location of the sensor

const int led1Pin = 3; //pin for LED corresponding to volume1
const int led2Pin = 4; //pin for LED corresponding to volume2

[Code] .....