qualified-id in declaration before '=' token / object counter variable - c++

Question

I'm trying to count how many instances or the class mole2 there are and store the number in a public static variable called mole_count.
mole2.h
#ifndef mole2_h
#define mole2_h
#include "Arduino.h"
class mole2 {
public:
mole2(int input, int output);
void popUp();
void popdown();
boolean moleBrainThinkPopUpNow();
void setUpTimer(int up_timer);
boolean didMoleGetHit();
void setRecoveryTimer(int recovery_timer);
void decrementRecoveryTimer();
boolean dosePlayerMistMole();
void moleReset();
int input, output;
static int mole_count;
static int odds_of_poping;
private:
boolean _is_popped = false;
int _up_timer = 0;
int _recovery_timer = 0;
};
#endif
mole2.cpp
#include "Arduino.h"
#include "mole2.h"
int mole2::odds_of_poping = 10;
mole2::mole2(int input, int output) {
input = input;
output = output;
int mole2::mole_count = mole2::mole_count + 1;
pinMode(input, INPUT);
pinMode(output, OUTPUT);
}
void mole2::popUp() {
_is_popped = true;
digitalWrite(input, HIGH);
}
void mole2::popdown() {
_is_popped = false;
digitalWrite(input, LOW);
}
boolean mole2::moleBrainThinkPopUpNow() {
if (_recovery_timer == 0 && _is_popped == false && rand() % odds_of_poping == 1) {
popUp();
return true;
}
else {
return false;
}
}
void mole2::setUpTimer(int up_timer) {
_up_timer = up_timer;
}
boolean mole2::didMoleGetHit() {
if (_is_popped == true && digitalRead(input) == HIGH) {
popdown();
_up_timer = 0;
return true;
}
else {
return false;
}
}
void mole2::setRecoveryTimer(int recovery_timer) {
_recovery_timer = recovery_timer;
}
void mole2::decrementRecoveryTimer() {
if (_recovery_timer > 0) {
_recovery_timer--;
}
}
boolean mole2::dosePlayerMistMole() {
if (_is_popped == true && _up_timer > 0) {
_up_timer--;
}
if (_is_popped == true && _up_timer == 0) {
popdown();
return true;
}
else {
return false;
}
}
void mole2::moleReset() {
popdown();
_up_timer = 0;
_recovery_timer = 0;
}
FullError
Arduino: 1.6.12 (Windows 7), Board: "Arduino/Genuino Uno"
C:\Users\Strings\Documents\Arduino\libraries\mole2\mole2.cpp: In constructor 'mole2::mole2(int, int)':
C:\Users\Strings\Documents\Arduino\libraries\mole2\mole2.cpp:9:25: error: qualified-id in declaration before '=' token
int mole2::mole_count = mole2::mole_count + 1;
^
exit status 1
Error compiling for board Arduino/Genuino Uno.
This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

Answer 1

First this:
int mole2::mole_count = mole2::mole_count + 1;
has no sense: you're declaring something and assigning it to its value + 1
Anyway, you already declared mole_count in your class. Since you're in the constructor, you're in the mole2 class already (the "qualified-id" bit comes from here), so you just have to do:
mole_count++;
Also, you have to declare storage for the variable in the .cpp class & initialize it:
int mole2::mole_count = 0;

Answer 2

You have to do the same thing as with odds_of_poping:
Definition:
int mole2::mole_count = 0; // initialization can be ommited as static variables are initialized to the default value
and later just increment: ++mole_count;

Answer 3

int mole2::mole_count has already been defined. This is trying to make another int mole2::mole_count. Lose the int and assign to the pre-existing variable.
You also need to allocate storage for and initialize mole_count. Place
int mole2::mole_count = 0; // replace 0 if starting with more than 0 mole2s
in somewhere around
int mole2::odds_of_poping = 10;
in mole2.cpp
Also watch out for
input = input;
output = output;
The compiler doesn't know whether you want to use the passed parameter input or the class's input so it will pick the closest defined input, the parameter, on both sides of the = . Refrain from reusing the same variable names in the same places at the same times.
This can be resolved by explicitely stating
this->input = input;
this->output = output;
Or (my favourite!) by using the member initializer list
mole2::mole2(int input, int output): input(input), output(output) {
But to prevent other confusion you should still not repeat the names.