rtd interfacing with arduino

Other Hardware Sensors
1

dear sir,
i am using pt100 with Wheatstone bridge circuit to measure the change in resistance. my input voltage to the Wheatstone bridge circuit is 5v from arduino. the output voltage at 33 degree Celsius is 0.19 to 0.20v. i can't measure the this voltage with arduino uno. and my Wheatstone bridge is balanced properly.
i haven't added any amplifier. i have connected the Wheatstone bridge circuit directly with arduino
i have attached my code here...
please reply me soon ... i am in need of this very urgently

int in_pin = A0;

void setup()
{
Serial.begin(9600);
}
void loop(0
{

int val = analogRead(in_pin);

double voltage = (5.0 / 1204.0) * val;

Serial.println(voltage);
delay(500);

}
2 
void loop(0
{

You haven't actually compiled this, have you?

double voltage = (5.0 / 1204.0) * val;

What does "1204" refer to?

3

thanks for reply me.....
that is

void loop()

i typed it wrongly......
and

double voltage = (5.0/1204.0)/val;

where 5.0 is the reference voltage
and since adc is 10 bit 1024 is the maximum number can be produced by adc......

4

So what does 1204 refer to?