diff --git a/matrix.c b/matrix.c
index 50e10ce..7e98811 100644
--- a/matrix.c
+++ b/matrix.c
@@ -5,6 +5,8 @@
 
 // TODO Matrix-Funktionen implementieren
 
+enum addModes{sameDimensions, colVec, rowVec};
+
 Matrix createMatrix(unsigned int rows, unsigned int cols)
 {
     Matrix m;
@@ -12,7 +14,7 @@ Matrix createMatrix(unsigned int rows, unsigned int cols)
     m.cols = cols;
     m.buffer = NULL;
  
-    if(rows == 0 || cols == 0)
+    if(rows == 0 || cols == 0) 
     {
         
         m.rows = 0;
@@ -22,6 +24,7 @@ Matrix createMatrix(unsigned int rows, unsigned int cols)
     }
  
     m.buffer = calloc(rows * cols, sizeof(MatrixType));
+    
     if (m.buffer == NULL)
     {
         
@@ -36,17 +39,36 @@ Matrix createMatrix(unsigned int rows, unsigned int cols)
 
 void clearMatrix(Matrix *matrix)
 {
+    if (matrix->buffer == NULL)
+    {
+        matrix->rows = 0;
+        matrix->cols = 0;
+        matrix->buffer = NULL;
+        return matrix;
+    }
+    else
+    {
+    
     free(matrix->buffer);
     
     matrix->rows = 0;
     matrix->cols = 0;
     matrix->buffer = NULL;
+
+    }
 }
 
 void setMatrixAt(MatrixType value, Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
 {
-   
-  matrix.buffer[(rowIdx * matrix.cols) + colIdx] = value;   //wir setzen den data-Wert an der Stelle (rowIdx*Spalten + colIdx) auf den Wert von value
+
+    if(matrix.buffer == NULL || rowIdx >= matrix.rows || colIdx >= matrix.cols)
+    {
+        return;
+    }
+    else
+    {
+        matrix.buffer[(rowIdx * matrix.cols) + colIdx] = value;   //wir setzen den data-Wert an der Stelle (rowIdx*Spalten + colIdx) auf den Wert von value
+    }
 }
 
 MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
@@ -59,110 +81,149 @@ MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int co
     return matrix.buffer[(rowIdx * matrix.cols) + colIdx];
 }
 
-static int can_add(Matrix matrix1, Matrix matrix2) {
+static int get_add_mode(Matrix matrix1, Matrix matrix2) {
 
-    int can_add;
+    int get_add_mode; 
 
     if(matrix1.cols == matrix2.cols && matrix1.rows == matrix2.rows){
 
-        can_add = 1;
+        get_add_mode = sameDimensions;
 
     }
     else if(matrix1.cols == 1 && matrix1.rows == matrix2.rows){
 
-        can_add = 2;
+        get_add_mode = colVec;
 
     }
     else if(matrix2.cols == 1 && matrix1.rows == matrix2.rows){
 
-        can_add = 3;
+        get_add_mode = colVec;
 
     }
     else if(matrix1.rows == 1 && matrix1.cols == matrix2.cols){
 
-        can_add = 4;
+        get_add_mode = rowVec;
 
     }
     else if(matrix2.rows == 1 && matrix1.cols == matrix2.cols){
 
-        can_add = 5;
+        get_add_mode = rowVec;
 
     }
-    else{
-
-        can_add = 0;
-
-    }
-
-    return can_add;
-    }
-
-Matrix add(const Matrix matrix1, const Matrix matrix2) //wir addieren nur wenn beide Matrizen gleich groß sind oder eine von beiden eine Zeile oder eine Spalte besitzt
-{
-    int ok = can_add(matrix1,matrix2);
+    return get_add_mode;
     
-    unsigned int erg_rows = (matrix1.rows == matrix2.rows) ? matrix1.rows : (matrix1.rows == 1 ? matrix2.rows : matrix1.rows);
-    unsigned int erg_cols = (matrix1.cols == matrix2.cols) ? matrix1.cols : (matrix1.cols == 1 ? matrix2.cols : matrix1.cols);
-    
-    Matrix matrix_erg = createMatrix(erg_rows, erg_cols);
+}
 
-    switch(ok)
+
+    Matrix addSameDim(Matrix matrix1, Matrix matrix2)
     {
-    case 1: 
-    
+        Matrix matrix_erg = createMatrix(matrix1.rows, matrix1.cols);
+
         for(int i = 0; i < (matrix1.rows * matrix1.cols); i++)
 
             matrix_erg.buffer[i] = matrix1.buffer[i] + matrix2.buffer[i];
+
+        return matrix_erg;    
+
+    }
+
+    Matrix addColVec(Matrix matrix1, Matrix matrix2)
+    {
+        Matrix matrix_erg;
+        if(matrix1.cols == 1)
+        {
+            matrix_erg = createMatrix(matrix2.rows, matrix2.cols);
+
+            for(int i = 0; i < matrix2.rows; i++)
+            {
+                for(int j = 0; j < matrix2.cols; j++)
+
+                    matrix_erg.buffer[i * matrix2.cols + j] = matrix1.buffer[i * matrix2.cols + j] + matrix2.buffer[i];
+            }
+            
+
+        }
+        if(matrix2.cols == 1)
+        {
+            matrix_erg = createMatrix(matrix1.rows, matrix1.cols);
+
+            for(int i = 0; i < matrix1.rows; i++)
+            {
+                for(int j = 0; j < matrix1.cols; j++)
+
+                    matrix_erg.buffer[i * matrix1.cols + j] = matrix1.buffer[i] + matrix2.buffer[i * matrix1.cols + j];
+            }
+        }
+        return matrix_erg;
+
+
+    }
+
+    Matrix addRowVec(Matrix matrix1, Matrix matrix2)
+    {
+        Matrix matrix_erg;
+        if(matrix1.rows == 1)
+        {
+            matrix_erg = createMatrix(matrix2.rows, matrix2.cols);
+
+            for(int i = 0; i < matrix2.rows; i++)
+            {
+                for(int j = 0; j < matrix2.cols; j++)
+
+                    matrix_erg.buffer[i * matrix2.cols + j] = matrix1.buffer[i * matrix2.cols + j] + matrix2.buffer[j];
+            }
+            
+
+        }
+        if(matrix2.rows == 1)
+        {
+            matrix_erg = createMatrix(matrix1.rows, matrix1.cols);
+
+            for(int i = 0; i < matrix1.rows; i++)
+            {
+                for(int j = 0; j < matrix1.cols; j++)
+
+                    matrix_erg.buffer[i * matrix1.cols + j] = matrix1.buffer[j] + matrix2.buffer[i * matrix1.cols + j];
+            }
+        }
+        return matrix_erg;
+    }
+
+
+    
+
+    Matrix add(const Matrix matrix1, const Matrix matrix2) 
+    {
+        int ok = get_add_mode(matrix1,matrix2);
+        
+        Matrix matrix_erg = createMatrix(0, 0); 
+    
+
+    switch(ok)
+    {
+    
+
+    case sameDimensions: 
+    
+        addSameDim(matrix1, matrix2);
             
         break;
 
-    case 2:
+    case colVec:
 
-        for(int i = 0; i < erg_rows; i++){
-            for(int j = 0; j < erg_cols; j++)
+        addColVec(matrix1, matrix2);
 
-                matrix_erg.buffer[i * erg_cols + j] = matrix1.buffer[i * erg_cols + j] + matrix2.buffer[i];
-        }
         break;
 
-    case 3:
+    case rowVec:
     
-        for(int i = 0; i < erg_rows; i++){
-            for(int j = 0; j < erg_cols; j++)
+        addRowVec(matrix1, matrix2);
 
-                matrix_erg.buffer[i * erg_cols + j] = matrix1.buffer[i] + matrix2.buffer[i * erg_cols + j];
-        }
         break;
 
-    case 4:
-
-        for(int i = 0; i < erg_rows; i++){
-            for(int j = 0; j < erg_cols; j++)
-
-                matrix_erg.buffer[i * erg_cols + j] = matrix1.buffer[i * erg_cols + j] + matrix2.buffer[j];
-        }
-        break;
-
-    case 5:
-    
-        for(int i = 0; i < erg_rows; i++){
-            for(int j = 0; j < erg_cols; j++)
-
-                matrix_erg.buffer[i * erg_cols + j] = matrix1.buffer[j] + matrix2.buffer[i * erg_cols + j];
-        }
-        break;
-
-    default:
-        
-        matrix_erg.rows = 0;
-        matrix_erg.cols = 0;
-        matrix_erg.buffer = NULL;
-        return matrix_erg;
-
-    
     }
 
-return matrix_erg;
+    return matrix_erg;
 
     
     
@@ -183,11 +244,11 @@ Matrix multiply(const Matrix matrix1, const Matrix matrix2)
     int ok = can_multiply(matrix1,matrix2);
     unsigned int erg_rows = matrix1.rows;
     unsigned int erg_cols = matrix2.cols;
-    Matrix matrix_erg = createMatrix(erg_rows, erg_cols);
-    
+    Matrix matrix_erg = createMatrix(0, 0);
     
     if (ok == 1)
     {
+        Matrix matrix_erg = createMatrix(erg_rows, erg_cols);
 
         for (int i = 0; i < erg_rows; i++)
         {
@@ -197,22 +258,15 @@ Matrix multiply(const Matrix matrix1, const Matrix matrix2)
                 
                 for (int k = 0; k < matrix1.cols; k++)
                 {
-                    sum += matrix1.buffer[i * matrix1.cols + k] * matrix2.buffer[k * matrix2.cols + j];
+                    sum += getMatrixAt(matrix1, k, j) * getMatrixAt(matrix2, j, k);
                 }
                 
-                matrix_erg.buffer [i * erg_cols + j] = sum;
+                setMatrixAt(sum, matrix_erg, i, j);
             }
  
         }
 
         return matrix_erg;
     }  
-    else 
-    {
-        
-        matrix_erg.rows = 0;
-        matrix_erg.cols = 0;
-        matrix_erg.buffer = NULL;
-        return matrix_erg;
-    }
+    
 }
\ No newline at end of file