Question

So i’m trying to better understand virtual methods.
I have a base class Sensor and several subclasses SensorTemp *SensorPh* SensorOrp

class Sensor
{
public:
virtual void updateValue();
}

the subclasses then override updateValue with their own method definitions (this happens in each of the subclasses)

.h file

#include "Sensor.h"
class SensorTemp : public Sensor
{
 private:


 public:

};

.Cpp file

#include "Sensor.h"
#include "SensorTemp.h"
void Sensor::updateValue(){
    int reading = analogRead(pinId); 
    float voltage = reading * 5.0;
    voltage /= 1024.0;
    currentVal = voltage * 100 ;
    Serial.print("temp: "); Serial.println(currentVal);
}

My issue is this works for the first subclass declaration, although the following will have a compiler error: updateValue() …. first defined here ld.exe : : Disabling relaxation: it will not work with multiple definitions

So I’m stuck on what type of approach I should take if I want to define the method differently from each subclass?

Any insight would be highly appreciated!

Answer 1

You subclass implementation should look like:

void SensorTemp::updateValue() {
    // ...
}