add casts

add inline
add template

CPlusPlus/Collections/main.cpp

@@ -31,6 +31,8 @@ int main()
 	int grid[COLUMNS * ROWS] = {};
 	grid[calculateIndex(3, 2)] = 10; // 4th column, 3rd row
 
+	//int grid2[10][10];
+
 	// size has to be always constant
 	const int count = 10;
 	int numbers4[count] = {};
@@ -58,6 +60,28 @@ int main()
 	delete[] pNumbers; // CAUTION - heap arrays have to be deleted with delete[]
 	pNumbers = pNumbers2 = nullptr;
 
+	// 2d heap array
+	int** pGrid = new int*[10];
+	cout << "grid starts at " << pGrid << endl;
+	for (size_t i = 0; i < 10; i++)
+	{
+		pGrid[i] = new int[10];
+		cout << i << ". row: " << &pGrid[i] << endl;
+		for (size_t j = 0; j < 10; j++)
+		{
+			cout << i << "/" << j << ": " << &pGrid[i][j] << endl;
+		}
+	}
+
+	// delete inner arrays first
+	for (size_t i = 0; i < 10; i++)
+	{
+		delete[] pGrid[i];
+		pGrid[i] = nullptr;
+	}
+	delete[] pGrid; // delete outer array second
+	pGrid = nullptr;
+
 	// stl collections
 	vector<int> numbers5;
 	vector<int> numbers6 = { 0, 1, 2, 3, 4 };