unsafe static void DemoAllocateOnHeap() // this can only be done using pointer
{
UnsafeStruct *structPtr = (UnsafeStruct *)Marshal.AllocHGlobal(sizeof(UnsafeStruct)); // it's compulsory to free this memory before exiting the method!
structPtr->IntField = 10;
structPtr->CharField = 'M';
structPtr->FloatArrayField[0] = 2.15f;
structPtr->FloatArrayField[2] = 3.25f;
Console.WriteLine("Int: " + structPtr->IntField);
Console.WriteLine("Char: " + structPtr->CharField);
Console.WriteLine("Array[0]: " + structPtr->FloatArrayField[0]);
Console.WriteLine("Array[1]: " + structPtr->FloatArrayField[1]); // on heap, the array is not auto-initialized- intially it contains garbage
Console.WriteLine("Array[2]: " + structPtr->FloatArrayField[2]);
Marshal.FreeHGlobal(new IntPtr(structPtr)); // don't free the memory and suffer memory leakage!!!
}
unsafe static void DemoAllocateOnStackViaPointer()
{
UnsafeStruct @struct;
UnsafeStruct *structPtr = &@struct; // there is no need to free memory since struct is created on stack and will be popped off when function exits
// Assign via pointer
structPtr->IntField = 10;
structPtr->CharField = 'M';
structPtr->FloatArrayField[0] = 2.15f;
structPtr->FloatArrayField[2] = 3.25f;
// Access normally
Console.WriteLine("Int: " + @struct.IntField);
Console.WriteLine("Char: " + @struct.CharField);
Console.WriteLine("Array[0]: " + @struct.FloatArrayField[0]);
Console.WriteLine("Array[1]: " + @struct.FloatArrayField[1]); // on stack the array is auto-initialized- there is no garbage
Console.WriteLine("Array[2]: " + @struct.FloatArrayField[2]);
}
