diff --git a/Startcode/matrix.c b/Startcode/matrix.c
index ad00628..04a312d 100644
--- a/Startcode/matrix.c
+++ b/Startcode/matrix.c
@@ -6,30 +6,100 @@
 
 Matrix createMatrix(unsigned int rows, unsigned int cols)
 {
-    
+    if(rows == 0 || cols == 0){
+        return (Matrix) {0, 0, NULL};       // Compound struct, kann für c99 verwendet werden 
+    }
+    MatrixType *arr = malloc(rows * cols * sizeof(MatrixType));
+    Matrix new_matrix = {rows, cols, arr};
+    return new_matrix;
 }
 
 void clearMatrix(Matrix *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)
 {
-    
+    if(rowIdx < matrix.rows && colIdx < matrix.cols){
+        *(matrix.buffer + rowIdx * matrix.rows + colIdx) = value;
+    }
 }
 
 MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
 {
-    
+    if(rowIdx >= matrix.rows || colIdx >= matrix.cols){
+        return 0;
+    }
+    return *(matrix.buffer + rowIdx * matrix.rows + colIdx);
 }
 
 Matrix add(const Matrix matrix1, const Matrix matrix2)
 {
+    int n1 = matrix1.cols;
+    int m1 = matrix1.rows;
+    int n2 = matrix2.cols;
+    int m2 = matrix2.cols;
+
+    if(n1 == 1 && m1 == m2){
+        Matrix new_mat = createMatrix(m2, n2);
+        for(int i = 0; i < m2; i++){
+            for(int j = 0; j < n2; j++){
+                *(new_mat.buffer + i * n2 + j) = *(matrix2.buffer + i * n2 + j) + *(matrix1.buffer + i);
+            }
+        }
+        return new_mat;
+    }
     
+    if(n2 == 1 && m1 == m2){
+        Matrix new_mat = createMatrix(m1, n1);
+        for(int i = 0; i < m1; i++){
+            for(int j = 0; j < n1; j++){
+                *(new_mat.buffer + i * n1 + j) = *(matrix1.buffer + i * n1 + j) + *(matrix2.buffer + i);
+            }
+        }
+        return new_mat;
+    }
+
+    if(n1 != n2 || m1 != m2){
+        return (Matrix) {0, 0, NULL};
+    }
+
+    Matrix new_mat = createMatrix(n1, m1);
+
+    for(int i = 0; i < m1; i++){
+        for(int j = 0; j < n1; j++){
+            *(new_mat.buffer + i * n1 + j) = *(matrix1.buffer + i * n1 + j) + *(matrix2.buffer + i * n1 + j);
+        }
+    }
+    return new_mat;
 }
 
 Matrix multiply(const Matrix matrix1, const Matrix matrix2)
 {
-    
+    int m = matrix1.rows;
+    int q = matrix1.cols;
+    int l = matrix2.cols;
+
+    if(q != matrix2.rows){
+        return (Matrix) {0, 0, NULL};
+    }
+
+    Matrix new_matrix = createMatrix(m, l);
+    MatrixType *new_mat_arr = new_matrix.buffer;
+
+    for(int i = 0; i < m; i++){
+        for(int j = 0; j < l; j++){
+            int sum = 0;
+            for(int k = 0; k < q; k++){
+                sum += *(matrix1.buffer + i * q + k) * *(matrix2.buffer + k * l + j);
+            }
+            *(new_mat_arr + i * l + j) = sum;
+        }
+    }
+
+    return new_matrix;
 }
\ No newline at end of file
diff --git a/Startcode/matrix.h b/Startcode/matrix.h
index cc640d1..e751efc 100644
--- a/Startcode/matrix.h
+++ b/Startcode/matrix.h
@@ -7,6 +7,12 @@ typedef float MatrixType;
 
 // TODO Matrixtyp definieren
 
+typedef struct {
+    int rows;
+    int cols;
+    MatrixType *buffer;
+} Matrix;
+
 
 Matrix createMatrix(unsigned int rows, unsigned int cols);
 void clearMatrix(Matrix *matrix);
diff --git a/Startcode/runMatrixTests b/Startcode/runMatrixTests
new file mode 100755
index 0000000..9de5604
Binary files /dev/null and b/Startcode/runMatrixTests differ