stdvector Questions
2
This is a follow up to this question, Restricted access for allocated arrays belonging to separate object, after discovering that returning by value across compilation units doesn't help to hint th...
Fauch asked 21/10 at 18:23
3
Solved
I noticed that the parameter of vector<T>::push_back is const T&. I know that a reallocation may take place when I call push_back, but vector<T>::back returns a reference. So ...
Joyce asked 7/9 at 9:18
3
Solved
I want to get a range of elements from a std::vector<MyClass> and store them as const-ref, because I only want to read but not modify them.
#include <iostream>
#include <vector>
...
2
The "four basic kinds" of C++ sequence containers
(vector, forward_list, list, and deque)
all have an assign method. For example, std::vector has
(quoting cppreference.com):
void as...
1
I know there are ways to either do or not do bounds-checking when indexing a vector, but specifically on push_back(), even if I know the capacity of the vector is large enough (i.e., I reserved eno...
4
I have a vector of bytes (std::vector ):
[1,1,1,9,9,9,1,1,1]
I want to replace bytes 3-6 with unknown length of bytes (I'll know at run time obv.).
So the length of the vector may grow, shirk or s...
4
I have Example Class:
class Example {
private:
int testValue1;
int testValue2;
int testValue3;
public:
Example(int pVal1, int pVal2, int pVal3);
Example(const Example);
const Example oper...
Durkheim asked 17/10, 2013 at 11:32
3
Solved
Language: C++
One thing I can do is allocate a vector of size n and store all data
and then sort it using sort(begin(),end()). Else, I can keep putting
the data in a map or set which are ordered i...
Revitalize asked 6/5, 2018 at 10:49
1
Solved
Overloading the operator bool() for a custom class T breaks std::vector<T> comparison operators.
The following code tried on the first online compiler google suggest me prints
v1 > v2: 0
v...
Avid asked 18/4 at 10:38
1
Solved
I noticed that the std::vector container's swap function has a different noexcept-specification than all other containers. Specifically, the function is noexcept if the expression
std::allocator_tr...
3
Solved
Why when I init std::vector with braces
std::vector<TS> vec {ts1, ts2};
Compiler call twice copy constructor operator? On the other hand - with push_back it called only once.
#include <...
Sonni asked 10/12, 2013 at 17:48
4
Solved
I wanted to do this
#include <vector>
#include <span>
struct S
{
std::vector<int> v;
void set(std::span<int> _v)
{
v = _v;
}
};
But it does not compile. What are the ...
3
Given a C++ vector (let's say it's of doubles, and let's call it unsorted), what is the most performant way to create a new vector sorted which contains a sorted copy of unsorted?
Consider the fol...
3
Solved
I write tools to dump and load common objects in a binary file. In a first quick implementation, I wrote the following code for std::vector<bool>. It works, but it is clearly not optimized in...
1
Solved
4
Solved
I have a std::vector<std::string> v; (initialized). How can I use the range-for loop for accessing all elements except the first one (on index zero). For all elements:
for (const string &...
4
Solved
I have a std::vector<std::string> m_vPaths; I iterate over this vector and call ::DeleteFile(strPath) as I go. If I successfully delete the file, I remove it from the vector.
My questio...
Erhart asked 22/10, 2009 at 1:37
2
Solved
Is the following code ok?:
std::vector<char> var;
size_t requiredSize;
getenv_s(&requiredSize, NULL, 0, "Something");
if (requiredSize == 0)
{
return ENV_NOT_EXIST;
}
if(var.size() <...
4
Solved
The code snippet below demonstrates a real issue I faced recently in my program:
#include<vector>
class A;
void f( const std::vector<A> & = {} );
There is an incomplete class A, ...
Fanciful asked 30/10, 2023 at 20:16
20
Solved
All I want to do is to check whether an element exists in the vector or not, so I can deal with each case.
if ( item_present )
do_this();
else
do_that();
5
Solved
if I do:
std::unique_ptr<int[]> uparr(new int[1984]);
and I pass uparr to somebody without passing the 1984 to them can they see how many elements it has?
aka is there equivalent of vector...
Moralize asked 26/3, 2014 at 13:21
4
Solved
I'm trying to read a file in binary format into a std::vector<std::byte>
std::ifstream fStream(fName, std::ios::binary);
std::vector<std::byte> file_content((std::istreambuf_iterato...
1
I can concisely (with braces) initialize 5 out of 6 of the following cases:
of copyable
of move-only
array
YES
YES
std::array
YES
YES
std::vector
YES
NO
The one case that doe...
Fabri asked 14/8, 2023 at 7:6
33
Solved
How do I print out the contents of a std::vector to the screen?
A solution that implements the following operator<< would be nice as well:
template<container C, class T, String delim = &q...
33
Solved
How do I print out the contents of a std::vector to the screen?
A solution that implements the following operator<< would be nice as well:
template<container C, class T, String delim = &q...
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