Question

I have two loops that iterate over an array of about 20 bools one after the other and print the memory address of each one:

for (int i = 0; i < 20; ++i) {
    printf("%p\n", &_boolArray[i]);
}
for (bool b : _boolArray) {
    b = true;
    printf("%p\n", &b);
}

I would expect the output to be exactly the same for both arrays. What I got was something a little different:

0x102eeefb0
0x102eeefb1
0x102eeefb2
0x102eeefb3
0x102eeefb4
0x102eeefb5
...
0x7fff5ce8b9bf
0x7fff5ce8b9bf
0x7fff5ce8b9bf
0x7fff5ce8b9bf
0x7fff5ce8b9bf

I know there are better ways to fill an array (std::fill for one), but I still want to know why this is happening.

Answer 1

You are making a copy of b in second for loop every time, should pass by reference

 for (bool &b : _boolArray) {
       //  ^^^ reference to original element
    b = true;
    printf("%p\n", &b);
}