Fixed compilation with -Wextra

src/arduinoFFT.h

@@ -435,13 +435,13 @@ private:
 #endif
 
 	/* Variables */
+	T *_vReal = nullptr;
+	T *_vImag = nullptr;
 	uint_fast16_t _samples = 0;
 #ifdef FFT_SPEED_OVER_PRECISION
 	T _oneOverSamples = 0.0;
 #endif
 	T _samplingFrequency = 0;
-	T *_vReal = nullptr;
-	T *_vImag = nullptr;
 	T *_windowWeighingFactors = nullptr;
 	FFTWindow _weighingFactorsFFTWindow;
 	bool _weighingFactorsWithCompensation = false;