How to delete 2d array?

Question

How do I delete this allocated pointer?

int (*foo)[4] = new int[100][4];

Is it just :

delete[] foo;

You're using new T[] with T being int[100]. Therefore, you need delete[], like any other T. — Qaz
– Qaz, Commented Jul 30, 2014 at 17:22
@chris, isn't the type int[4] actually? int (*foo)[4] declares a pointer to array-of-4-int, then you allocate 100 such arrays. — vsoftco
– vsoftco, Commented Jul 30, 2014 at 18:17
@vsoftco, Oops, that's right. Not sure why I put int[100]. — Qaz
– Qaz, Commented Jul 30, 2014 at 18:26
First I am not sure if that`s how you initialize a double pointer. Second, its seems you have a pointer foo; that points to four pointers. To avoid memory leak you have to delete all pointers and not just one. So you need to: delete foo[0]; delete foo[1]; delete foo[2]; delete foo[3]; and then delete foo; All these are pointers. — Juniar
– Juniar, Commented Jul 30, 2014 at 18:45
@Juniar, it is not a double pointer, it is a pointer to a data type defined as int[4] (that occupies 4 contiguous ints), so in the memory looks like {X X X X} -> {X X X X} -> ... 100 times ... -> {X X X X } — vsoftco
– vsoftco, Commented Jul 30, 2014 at 18:47

Vlad from Moscow · Accepted Answer · 2014-07-30 17:27:17Z

5

As you have allocated an array you have to use operator delete[]

delete []foo;

That it would be more clear you can rewrite the code snippet the following way

typedef int T[4];

T *foo = new T[100];

delete []foo;

answered Jul 30, 2014 at 17:21

Vlad from Moscow

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