diff --git a/matrix.c b/matrix.c
index d1c4bd1..b0c4786 100644
--- a/matrix.c
+++ b/matrix.c
@@ -6,36 +6,49 @@
 
 Matrix createMatrix(unsigned int rows, unsigned int cols)
 {
+    if(rows <= 0 || cols <= 0){
+        Matrix matrix = { 0 , 0 , UNDEFINED_MATRIX_VALUE };
+        return matrix;
+    }
+
     Matrix matrix = { rows , cols };
 
-    matrix.matrixptr = malloc((sizeof(MatrixType)*rows*cols));
+    matrix.buffer = malloc((sizeof(MatrixType)*rows*cols));
 
     return matrix;
 }
 
 void clearMatrix(Matrix *matrix)
 {
-   free(*matrix);
+   free(matrix->buffer);
+
+    matrix->buffer = NULL;
+    matrix->rows = 0;
+    matrix->cols = 0;
 }
 
 void setMatrixAt(MatrixType value, Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
 {
-    *(matrix.matrixptr+(rowIdx*colIdx)) = value;
+    *(matrix.buffer + (rowIdx * matrix.cols + colIdx)) = value;
+
 }
 
 MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
 {
+    if(matrix.rows <= rowIdx || matrix.cols <= colIdx)
+    return UNDEFINED_MATRIX_VALUE;
+
     MatrixType value;
-    matrix[rowIdx][colIdx] = value;
+    value = *(matrix.buffer + (rowIdx * matrix.cols + colIdx));
     return value;
 }
 
 Matrix add(const Matrix matrix1, const Matrix matrix2)
 {
-    
+    return matrix1;
 }
 
 Matrix multiply(const Matrix matrix1, const Matrix matrix2)
 {
-    
+    return matrix1;
 }
\ No newline at end of file
diff --git a/matrix.h b/matrix.h
index 41ae1dd..49c981d 100644
--- a/matrix.h
+++ b/matrix.h
@@ -8,7 +8,7 @@ typedef float MatrixType;
 typedef struct{
     unsigned int rows;
     unsigned int cols;
-    int *martix_ptr;
+    MatrixType *buffer;
 }Matrix;
 // TODO Matrixtyp definieren