Trash on Arduino serial monitor. How to fix it? - c++

Question

i'm working with I2C eeprom and Arduino. For now i tried to create simple keyboard that will start specific functions. I want to write to serial monitor potentiometer value, but i get trash instead it. How to fix it?
My functions:
int *readPot() ///read potentiometer value
{
int tempValue = analogRead(A0);
int *potValue = &tempValue;
return potValue;
}
void keyboardProcess() ///process keyboard input
{
int *potValue = readPot();
for(int i = 0; i < 2; i++)
{
btnReadings[i] = digitalRead(keysPins[i]);
}
if(btnReadings[0] == HIGH)
{
Serial.println("Potentiometer reading:" + *potValue);
}
}

Answer 1

One obvious problem is that you are returning the address to a local variable:
int *readPot() ///read potentiometer value
{
int tempValue = analogRead(A0);
int *potValue = &tempValue;
return potValue;
}
Here, the returned pointer points to the address of tempValue. This ceases to be valid once the function returns. Just use an int:
int readPot() ///read potentiometer value
{
return analogRead(A0);
}
Next, I doubt that this is a valid argument to Serial.println:
Serial.println("Potentiometer reading:" + *potValue);
but this should work:
int potValue = readPot();
Serial.print("Potentiometer reading: ");
Serial.println(potValue);