A code for i2C 16*2 LCD, 3LEDs, LM35 sensor

Yes. You definately have to expand from there.
OP wants to read with 0.1C accuracy.
This:

int tempReading = analogRead(tempPin);
float tempVolts = tempReading * 5.0 / 1024.0;
float tempC = (tempVolts - 0.5) * 100.0;
float tempF = tempC * 9.0 / 5.0 + 32.0;

is an example of bad code for an LM35 temp sensor.
One degree C accurate if you're lucky.
Leo..