Difference between : &data[0] vs. data

Question

When I want to pass an array by reference to a function I don't know what to choose.

void myFunction(int* data);

Is there a difference or a best coding way between those two cases:

myFunction(&data[0]);

Or

myFunction(data);

Answer 1

There is no difference. Arrays ("proper" arrays) automatically decay to pointers to their first element.

For example, lets say you have

int my_array[10];

then using plain my_array will automatically decay to a pointer to its first element, which is &my_array[0].

It is this array-to-pointer decay that allows you to use both pointer arithmetic and array indexing for both arrays and pointers. For the array above my_array[i] is exactly equal to *(my_array + i). This equivalence also exists for pointers:

int *my_pointer = my_array;  // Make my_pointer point to the first element of my_array

Then my_pointer[i] is also exactly equal to *(my_pointer + i).

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For curiosity (and something you should never do in real programs), thanks to the commutative property of addition an expression such as *(my_array + i) will also be equal to *(i + my_array) which is then equal to i[my_array].