diff --git a/MMS24-25.c b/MMS24-25.c
index c589041..eda12d1 100644
--- a/MMS24-25.c
+++ b/MMS24-25.c
@@ -399,10 +399,10 @@ void deleteExtrema(Extrema *pexIn) {
 }
 
 void initMMSignalFeatures(MMSignal *pmmsIn) {
-    pmmsIn->dArea = calculateArea(pmmsIn->pdValues, pmmsIn->iNumValues);
-    pmmsIn->dMean = calculateMean(pmmsIn->pdValues, pmmsIn->iNumValues);
-    pmmsIn->dStdDev = calculateStddev(pmmsIn->pdValues, pmmsIn->iNumValues);
-    pmmsIn->dMedian = calculateMedian(pmmsIn->pdValues, pmmsIn->iNumValues);
+    pmmsIn->dArea = 0;
+    pmmsIn->dMean = 0;
+    pmmsIn->dStdDev = 0;
+    pmmsIn->dMedian = 0;
     pmmsIn->pexExtrema = initExtrema(pmmsIn->pdValues, pmmsIn->iNumValues);
 }
 
@@ -496,3 +496,37 @@ MMSignal *getPascalLine(int iLinenum) {
 }
 
 // #endregion
+
+// #region Aufgabe 4
+void computeDFT(int iLen,
+		double *pdRealIn, double *pdImgIn,
+		double *pdRealOut, double *pdImgOut,
+		int iDirection /*-1,1*/) {
+	// Check the value of iDirection
+	if (iDirection != -1 && iDirection != 1)
+        _error("computeDFT: iDirection must be either -1 or 1\n");
+
+	for (int k = 0; k < iLen; k++) {
+        pdRealOut[k] = 0;
+        pdImgOut[k] = 0;
+        for (int n = 0; n < iLen; n++) {
+            pdRealOut[k] += pdRealIn[n] * cos(2*M_PI *k *n / iLen) + iDirection * pdImgIn[n] * sin(2*M_PI *k *n / iLen);
+            pdImgOut[k] += -iDirection * pdRealIn[n] * sin(2*M_PI *k *n / iLen) + pdImgIn[n] * cos(2*M_PI *k *n / iLen);
+        }
+    }
+}
+
+void convertCart2Polar(double *pdRealIn, double *pdImgIn, double *pdRadiusOut, double *pdAngleOut, int iLen) {
+    for (int i = 0; i < iLen; i++) {
+        pdRadiusOut[i] = sqrt(pow(pdRealIn[i], 2) + pow(pdImgIn[i], 2));
+        pdAngleOut[i] = atan2(pdImgIn[i], pdRealIn[i]);
+    }
+}
+
+void convertPolar2Cart(double *pdRadiusIn, double *pdAngleIn, double *pdRealOut, double *pdImgOut, int iLen) {
+    for (int i = 0; i < iLen; i++) {
+        pdRealOut[i] = pdRadiusIn[i] * cos(pdAngleIn[i]);
+        pdImgOut[i] = pdRadiusIn[i] * sin(pdAngleIn[i]);
+    }
+}
+// #endregion