Comparing arrays for equality in C++

Question

Can someone please explain to me why the output from the following code is saying that arrays are not equal?

int main()
{

    int iar1[] = {1,2,3,4,5};
    int iar2[] = {1,2,3,4,5};

    if (iar1 == iar2)
        cout << "Arrays are equal.";
    else
        cout << "Arrays are not equal.";

    return 0;   
}

Answer 1

if (iar1 == iar2)

Here iar1 and iar2 are decaying to pointers to the first elements of the respective arrays. Since they are two distinct arrays, the pointer values are, of course, different and your comparison tests not equal.

To do an element-wise comparison, you must either write a loop; or use std::array instead

std::array<int, 5> iar1 {1,2,3,4,5};
std::array<int, 5> iar2 {1,2,3,4,5};

if( iar1 == iar2 ) {
  // arrays contents are the same

} else {
  // not the same

}