I have a class respectively a struct with a member variable of type std::array<char, 100> called charArray. I want to initialize this array sensibly. Which values are sensible to init the array with and what is the best way to do this?
I think I could use std::fill() in constructor but is this the way I should really do it? I mean because of initialization vs. assignment?
Thanks.
A simple solution would be to value initialize the array to the type's default value. Take for example
struct Foo
{
std::array<int, 10> bar;
Foo() : bar({}) {}
};
Here bar is would be initialized to all 0's. You can compare that with
struct Bar
{
std::array<int, 10> baz;
};
Which would default initialize baz and its elements would have an indeterminate value. You can see all of this working with
struct Foo
{
std::array<int, 10> bar;
Foo() : bar({}) {}
};
struct Bar
{
std::array<int, 10> baz;
};
int main(){
Foo foo;
for (auto e : foo.bar)
std::cout << e << " ";
std::cout << std::endl;
Bar bar;
for (auto e : bar.baz)
std::cout << e << " ";
}
Possible output:
0 0 0 0 0 0 0 0 0 0
-917263728 4197632 4197632 4197632 4197632 4197632 6295552 0 4197581 0
bar.baz behind the screen of iterators and operator calls) undefined behavior "if the object is uninitialized". DR 616 will not change that for automatic variables. The reason must be architectures with "uninitialized" flags or outright trap representations in registers.