When I use new[] to create an array of my classes:
int count = 10;
A *arr = new A[count];
I see that it calls a default constructor of A
count
times. As a result arr
has count
initialized objects of type A
.
But if I use the same thing to construct an int array:
int *arr2 = new int[count];
it is not initialized. All values are something like -842150451
though default constructor of int assignes its value to 0
.
Why is there so different behavior? Does a default constructor not called only for built-in types?
See the accepted answer to a very similar question. When you use new[]
each element is initialized by the default constructor except when the type is a built-in type. Built-in types are left unitialized by default.
To have built-in type array default-initialized use
new int[size]();