Assigning one array to another array c++ [duplicate]

Answer 1

The array is silently (implicitly) converted to a pointer in the function declaration, and the pointer is copied. Of course the copied pointer points to the same location as the original, so you can modify the data in the original array via the copied pointer in your function.

Answer 2

It isn't copying the array; it's turning it to a pointer. If you modify it, you'll see for yourself:

void f(int x[]) { x[0]=7; }
...
int tst[] = {1,2,3};
f(tst); // tst[0] now equals 7

If you need to copy an array, use std::copy:

int a1[] = {1,2,3};
int a2[3];
std::copy(std::begin(a1), std::end(a1), std::begin(a2));

If you find yourself doing that, you might want to use an std::array.