Question

Suppose I have an array of objects of type Foo in C++:

Foo array[10];

In Java, I can set an object in this array to null simply by:

array[0] = null //the first one

How can I do this in C++?

Answer 1

Use pointers instead:

Foo *array[10];

// Dynamically allocate the memory for the element in `array[0]`
array[0] = new Foo();
array[1] = new Foo();

...

// Make sure you free the memory before setting 
// the array element to point to null
delete array[1]; 
delete array[0]; 

// Set the pointer in `array[0]` to point to nullptr
array[1] = nullptr;
array[0] = nullptr;

// Note the above frees the memory allocated for the first element then
// sets its pointer to nullptr. You'll have to do this for the rest of the array
// if you want to set the entire array to nullptr.

Note that you need to consider memory management in C++ because unlike Java, it does not have a Garbage Collector that will automatically clean up memory for you when you set a reference to nullptr. Also, nullptr is the modern and proper C++ way to do it, as rather than always is a pointer type rather than just zero.