This question already has answers here:
Does C++ zero-initialise unspecified values during aggregate initialization?
(2 answers)
Why would my array would be filled out to zero, when I initialised it to -1
(5 answers)
how does array[100] = {0} set the entire array to 0?
(4 answers)
Closed 6 months ago.
I have a constructor that looks like
A (const int(&inArr)[4])
{
...
}
And I can construct an instance with list-initialization as such,
A a({3,4,5,6});
However, I can also construct an instance with a shorter list, e.g. {3,2}, or an empty list {}. From my testing in MSVC and Clang, the array received by the constructor is always zeroed after the values in the list. i.e. {3,2} will be read as [3,2,0,0], and {} as [0,0,0,0].
I am wondering if this is standard behaviour that can be relied upon, or if this may vary across platforms/compilers?
This question already has answers here:
Getting reference to the raw array from std::array
(5 answers)
How do you declare a pointer to a C++11 std::array?
(4 answers)
Can we use conventional pointer arithmetic with std::array?
(6 answers)
Closed 1 year ago.
I need to interface C++ code to a C library. I have a std::array:
std::array<uint8_t, buffer_size> send;
Stuff gets written to send, and then I need to pass a pointer to this data to a C function. I'm not sure the best way to do that.
Here is my best guess:
write(fd, &send[0], size); // c function
This question already has answers here:
c++ initial value of dynamic array
(6 answers)
How can I make `new[]` default-initialize the array of primitive types?
(4 answers)
Initialization of array on heap
(7 answers)
C++: new call that behaves like calloc?
(11 answers)
Operator new initializes memory to zero
(4 answers)
Closed 3 years ago.
What it the initial values of an array declared in the heap. it's a zero or random values in memory?
int* ptrAr;
ptrAr = new int[5];
This question already has answers here:
What are the evaluation order guarantees introduced by C++17?
(3 answers)
Order of evaluation of assignment statement in C++
(4 answers)
Closed 4 years ago.
Consider this code:
std::unordered_map<int, std::string> data;
data[5] = foo();
In what order are data[5] and foo() processed? If foo() throws an exception, is the 5 item in data created or not?
If the behaviour depends on version of C++, how do those versions differ?
This question already has answers here:
Is there a difference between copy initialization and direct initialization?
(9 answers)
Direct Initialization vs Copy Initialization for Primitives
(4 answers)
Closed 9 years ago.
I read the following code in c++:
bool result(false);
is result initialized as false?
but are there any benefits to do it instead of:
bool result = false;
can anyone help?