Access values inside array using pointers

Question

I've noticed in golang that we can use a pointer to an array as follows:

arr := [3]int{1, 2, 3}
var ptr *[3]int = &arr

To get value stored at an index n we can do (*ptr)[n], but why does ptr[n] also fetch me the value, Shouldn't it output some random address ?

Context

In C++, this is the observed behaviour


int (*ptr)[5];
int arr[] = {1,2,3,4,5};

ptr = &arr;
cout <<"ptr[1] = " << ptr[1] <<endl; //Outputs an address (base address of array + 20bytes)
cout << "(*ptr)[1] = " << (*ptr)[1]<< endl; //Outputs 2

In C++ there is array-to-pointer decay (implicit conversion from values of array type to values of pointer type), but no the same conversion in Go. — rustyhu
– rustyhu, Commented Oct 17, 2021 at 10:55
Go deliberately omits all the horrible things you can do to yourself with pointers in C and C++. The result is that you can't accidentally shoot yourself in the foot (C), or accidentally create numerous instances of yourself and shoot all of them in the foot (C++). See also www-users.cs.york.ac.uk/susan/joke/foot.htm — torek
– torek, Commented Oct 17, 2021 at 12:59

mkopriva · Accepted Answer · 2021-10-17 10:56:18Z

3

For a of pointer to array type:

a[x] is shorthand for (*a)[x]

See language spec: Index Expressions.

answered Oct 17, 2021 at 10:56

mkopriva

38.7k4 gold badges72 silver badges86 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Access values inside array using pointers

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related