const-iterator Questions
10
Solved
I have a custom container class for which I'd like to write the iterator and const_iterator classes.
I never did this before and I failed to find an appropriate how-to. What are the guidelines reg...
Floriated asked 27/8, 2010 at 8:50
10
Solved
As an extension to this question Are const_iterators faster?, I have another question on const_iterators. How to remove constness of a const_iterator?
Though iterators are generalised form of poin...
Culhert asked 19/4, 2009 at 9:54
4
Solved
I have written following code snippet but it does not seem to be working.
int main(){
int VCount, v1, v2;
pair<float, pair<int,int> > edge;
vector< pair<float, pair<int,int...
Ceroplastic asked 1/9, 2014 at 12:41
3
Solved
I want to change the element in a set, so I used set<T>::iterator. However, the compiler argues "the element is const". Then I realized that set<T>::iterator is a const_iterator...
So,...
Gadroon asked 7/3, 2012 at 11:31
7
Solved
I wonder why cbegin and cend were introduced in C++11?
What are cases when calling these methods makes a difference from const overloads of begin and end?
Noni asked 17/8, 2012 at 7:16
8
Solved
I made a collection for which I want to provide an STL-style, random-access iterator. I was searching around for an example implementation of an iterator but I didn't find any. I know about the nee...
Nonparous asked 8/11, 2011 at 17:6
1
Let's say I'm implementing a collection, say something like std::vector. I need to implement iterator and const_iterator, but once I've made iterator can const_iterator not just be implemented as i...
Talented asked 17/6, 2019 at 1:19
1
Solved
According to this answer, an iterator must be implicitly convertible to const_iterator. Since that is true, as we can see happening in insert_or_assign(), then why in C++17 was a new signature adde...
Conclusion asked 8/6, 2018 at 16:26
2
Solved
I have this piece of code:
auto it = my_map.lower_bound(my_key);
The following assert gives me error:
static_assert(std::is_same<decltype(it), std::map<K, V>::const_iterator>::value...
Gallicism asked 6/6, 2018 at 17:23
2
C++98 containers defined two kinds of iterator, ::iterators and ::const_iterators. Generally, like this:
struct vec{
iterator begin() ;
const_iterator begin() const;
};
In C++11 this part of the...
Amorous asked 21/2, 2018 at 21:37
2
Solved
Considering the code below,
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int main(){
vector<int> value{22, 23, 25, 34, 99};
auto it = ...
Pozsony asked 11/2, 2018 at 3:27
6
Solved
Someone here recently brought up the article from Scott Meyers that says:
Prefer iterators over const_iterators (pdf link).
Someone else was commenting that the article is probably outdated. I...
Fossil asked 19/4, 2009 at 11:28
2
Solved
Let say I define some kind of container A:
struct A
{
iterator begin(){ return iterator(this,0); }
const iterator cbegin() const { return iterator(this, last());}
//...
};
Suppose now I want ...
Allelomorph asked 3/7, 2017 at 9:43
3
Solved
What is difference between these two regarding implementation inside STL.
what is the difference regarding performance?
I guess when we are traversing the vector in "read only wise", we prefe...
Parnassus asked 18/3, 2011 at 0:45
1
Solved
See, e.g., http://en.cppreference.com/w/cpp/container/map/erase
In C++03 there were three overloads:
void erase( iterator pos );
void erase( iterator first, iterator last );
size_type erase( cons...
Galloglass asked 21/12, 2016 at 6:47
2
Solved
I was under the impression one cant use erase on a const iterator. Check this code.
Why does the below code compile (C++11, gcc)?
long getMax(const bool get_new)
{
long max_val=0;
TO now=getNow...
Taxexempt asked 21/12, 2016 at 5:13
1
Solved
The comment at Why does boost::find_first take a non-const reference to its input? suggests "the caller to create a non-const iterator_range with const_iterator template parameter to "prove" that t...
Doublebreasted asked 1/4, 2016 at 20:23
3
Solved
Consider the following code:
#include <vector>
#include <iostream>
int main()
{
std::vector<int> vec{1,2,3,5};
for(auto it=vec.cbegin();it!=vec.cend();++it)
{
std::cout <...
Prefigure asked 14/2, 2016 at 10:43
1
Solved
I am trying to write a class that should act as a sorted view on some underlying sequence of elements. So far I have come up with a non-const version. Now I have problems adapting it to also provid...
Nobe asked 8/10, 2015 at 15:48
2
Solved
This code is a simplified test for something I am trying to do for real elsewhere. I have a function which takes a "ref-to-ptr" argument and modifies it to return a pointer from a list of pointers....
Geezer asked 23/6, 2015 at 13:32
2
Solved
General goal
I manage a collection of objects (Collection of Real as simple example). Then I defined iterators on my collection. That means : iterator, const_iterator, reverse_iterator and const_r...
Meadors asked 8/6, 2015 at 14:7
2
Solved
Here is my code:
#include <set>
#include <iostream>
using namespace std;
int main(){
set<int> st;
st.insert(1);
int x = st.find(1) - st.begin();
return 0;
}
I am getting ...
Electrolysis asked 21/4, 2015 at 6:12
4
Solved
#include <string>
#include <iostream>
int main() {
std::string s = "abcdef";
std::string s2 = s;
auto begin = const_cast<std::string const &>(s2).begin();
auto end = s2...
Flange asked 26/2, 2015 at 17:1
3
// Cat.h
class Cat
{public:
void const_meow() const{ ... };
void meow(){ ... };
};
class CatLibrary
{public:
std::vector<std::shared_ptr<Cat>>::iterator begin()
{
return m_cat_...
Thorlay asked 6/8, 2014 at 6:7
2
Solved
With the advent of C++11, we have unordered_map.cbegin/cend to specifically return us values of const_iterator. so the deduced type of 'it' in the expression "auto it = unordered_map.cbegin()" is c...
Bracteole asked 21/8, 2013 at 18:41
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