identifier "test" is undefined; What does this mean in this context - c++

Question

I am writing a weather station for a raspberry. I'm always getting the error message identifier "test" is undefined.
I've already tried to use no external class with a little example and this works perfectly. Now I'm trying to create an object test, but this doesn't work. I am always getting the error message:
E0020 identifier "test" is undefined
main.cpp:
#include <wiringPi.h>
#include <stdio.h>
#include <iostream>
#include <cstring>
#include <errno.h>
#include <stdlib.h>
include "MeasureWeather.h"
int main(void)
{
MeasureWeather test;
while (1)
{
test._setSensorPin(DHT_PIN);
}
return 0;
}
MeasureWeather.h:
#ifndef MeasureWeather
#define MeasureWeather
#include <wiringPi.h>
#include <stdio.h>
#include <iostream>
#include <errno.h>
#include <stdlib.h>
#include <cstring>
class MeasureWeather
{
public:
//setter for sensor pin
void _setSensorPin(uint8_t pin);
private:
uint8_t sensorPin;
};
#endif // !MeasureWeather
MeasureWeather.cpp:
include "MeasureWeather.h"
void MeasureWeather::setSensorPin(uint8_t pin)
{
_sensorPin = pin;
}
I hope somebody can help me with my issue. Thank you!

Answer 1

You have this at the top of your header file, as part of the include guard:
#define MeasureWeather
MeasureWeather is the name of your class. By defining it as a macro, you hide the class name. Thus the line
MeasureWeather test;
expands to
test;
which would be a reference to something called test, not a declaration.
Use a different identifier for your #include guard.