Finding RPM of wheel using IR sensor

I tried a program to find the rpm of a wheel using an IR sensor... i dont have hardware ready now, so i cant check it
pls tell me if this will work

int count=0;                           //number of rotates
unsigned int r;                        //rotates per minute 
unsigned long int pretime=0;           //previous time

void setup()
{
  Serial.begin(9600);
  pinMode(2,0);                        //IR sensor at pin 2
  attachInterrupt(0,cnt,RISING);       //function cnt called when
}                                      //IR output signal goes from LOW to HIGH 

void loop()
{
  unsigned long int curtime=millis();  //current time 
  if((curtime-pretime)>5000)           //calculating rpm every 5 second
    r=count/(curtime-pretime)*1000*60;
  Serial.print("count : ");
  Serial.println(count);
  Serial.print("rpm : ");
  Serial.println(r);
  pretime=millis();                    //updating previous time and count
  count=0;
  delay(1000);
}

void cnt()
{
  count++;
}

This seems to be a duplicate of this - which is where the discussion is happening.

Please don't start a separate Thread on the same thing,

...R