Implement matrix.c

Startcode/matrix.c

@@ -2,34 +2,129 @@
 #include <string.h>
 #include "matrix.h"
 
-// TODO Matrix-Funktionen implementieren
-
+// Matrix erstellen
 Matrix createMatrix(unsigned int rows, unsigned int cols)
 {
-    
+    Matrix matrix;
+
+    matrix.rows = rows;
+    matrix.cols = cols;
+
+    matrix.data = calloc(rows * cols, sizeof(MatrixType));
+
+    if (matrix.data == NULL)
+    {
+        matrix.rows = 0;
+        matrix.cols = 0;
+    }
+
+    return matrix;
 }
 
-void clearMatrix(Matrix *matrix)
+// Matrix-Speicher freigeben
+void clearMatrix(Matrix* matrix)
 {
-    
+    if (matrix != NULL)
+    {
+        free(matrix->data);
+
+        matrix->data = NULL;
+        matrix->rows = 0;
+        matrix->cols = 0;
+    }
 }
 
-void setMatrixAt(MatrixType value, Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
+// Wert an einer bestimmten Position setzen
+void setMatrixAt(MatrixType value, Matrix matrix,
+                 unsigned int rowIdx, unsigned int colIdx)
 {
-    
+    if (matrix.data != NULL &&
+        rowIdx < matrix.rows &&
+        colIdx < matrix.cols)
+    {
+        matrix.data[rowIdx * matrix.cols + colIdx] = value;
+    }
 }
 
-MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
+// Wert an einer bestimmten Position auslesen
+MatrixType getMatrixAt(const Matrix matrix,
+                       unsigned int rowIdx, unsigned int colIdx)
 {
-    
+    if (matrix.data != NULL &&
+        rowIdx < matrix.rows &&
+        colIdx < matrix.cols)
+    {
+        return matrix.data[rowIdx * matrix.cols + colIdx];
+    }
+
+    return UNDEFINED_MATRIX_VALUE;
 }
 
+// Zwei Matrizen addieren
 Matrix add(const Matrix matrix1, const Matrix matrix2)
 {
-    
+    if (matrix1.rows != matrix2.rows ||
+        matrix1.cols != matrix2.cols ||
+        matrix1.data == NULL ||
+        matrix2.data == NULL)
+    {
+        return createMatrix(0, 0);
+    }
+
+    Matrix result = createMatrix(matrix1.rows, matrix1.cols);
+
+    if (result.data == NULL)
+    {
+        return result;
+    }
+
+    for (unsigned int i = 0; i < matrix1.rows; i++)
+    {
+        for (unsigned int j = 0; j < matrix1.cols; j++)
+        {
+            MatrixType value =
+                getMatrixAt(matrix1, i, j) +
+                getMatrixAt(matrix2, i, j);
+
+            setMatrixAt(value, result, i, j);
+        }
+    }
+
+    return result;
 }
 
+// Zwei Matrizen multiplizieren
 Matrix multiply(const Matrix matrix1, const Matrix matrix2)
 {
-    
-}
+    if (matrix1.cols != matrix2.rows ||
+        matrix1.data == NULL ||
+        matrix2.data == NULL)
+    {
+        return createMatrix(0, 0);
+    }
+
+    Matrix result = createMatrix(matrix1.rows, matrix2.cols);
+
+    if (result.data == NULL)
+    {
+        return result;
+    }
+
+    for (unsigned int i = 0; i < matrix1.rows; i++)  // nur < weil bei 0 angefangen zu zählen
+    {
+        for (unsigned int j = 0; j < matrix2.cols; j++)
+        {
+            MatrixType sum = 0;
+
+            for (unsigned int k = 0; k < matrix1.cols; k++)
+            {
+                sum += getMatrixAt(matrix1, i, k) *
+                    getMatrixAt(matrix2, k, j);
+            }
+
+            setMatrixAt(sum, result, i, j);
+        }
+    }
+
+    return result;
+}