I see no software person has answered you. I am a hardware person.
Get the data sheet for the LM35. It has a temperature to voltage graph.
ADCs in micro controllers do not measure voltage directly. In 8 bit mode they measure from 0 to 255. Where 0=0 volts and 255=vref.
You need to think; at freezing=some voltage from the LM35 and a certain ADC reading.
At boiling= a LM35 voltage and a ADC reading. (based on the value of VREF)
With some math you should be able to connect temperature to ADC reading.