mutiplyMatrix implementierung

Startcode/matrix.c

@@ -2,6 +2,8 @@
 #include <string.h>
 #include "matrix.h"
 
+#include <stdio.h>
+
 // TODO Matrix-Funktionen implementieren
 
 Matrix createMatrix(unsigned int rows, unsigned int cols)
@@ -38,8 +40,12 @@ void setMatrixAt(MatrixType value, Matrix matrix, unsigned int rowIdx, unsigned
 
 MatrixType getMatrixAt(const Matrix matrix, unsigned int rowIdx, unsigned int colIdx)
 {
-    MatrixType testHelp = 0;
-    return testHelp;
+    if(matrix.rows > rowIdx && matrix.cols > colIdx){
+        return matrix.buffer[colIdx + rowIdx * matrix.cols];
+    }else{
+        return UNDEFINED_MATRIX_VALUE;
+    }
+    
 }
 
 Matrix add(const Matrix matrix1, const Matrix matrix2)
@@ -50,6 +56,33 @@ Matrix add(const Matrix matrix1, const Matrix matrix2)
 
 Matrix multiply(const Matrix matrix1, const Matrix matrix2)
 {
-    Matrix testHelp = {NULL, 0,0};
-    return testHelp;
+    Matrix resultMatrix = createMatrix(matrix1.rows,matrix2.cols);
+    
+    if(matrix1.cols == matrix2.rows){
+        unsigned int commonDimension = matrix1.cols;
+
+        for(int i = 0; i < resultMatrix.rows; i++){
+            
+            for(int j = 0; j < resultMatrix.cols; j++){
+                MatrixType entry = 0;
+                
+                for(int k = 0; k < commonDimension; k++){
+                    entry += (matrix1.buffer[k + i * matrix1.cols] * matrix2.buffer[j + k * matrix2.cols]);
+                }
+
+                resultMatrix.buffer[j + i * resultMatrix.cols] = entry;
+            }
+        } 
+
+        return resultMatrix;
+    }else{
+        resultMatrix.buffer = NULL;
+        resultMatrix.rows = 0;
+        resultMatrix.cols = 0;
+        return resultMatrix;
+    }
+
+
+
+    
 }