c++ - Assigning to an element via iterator -


i thought can assign new value elemnt of container through non-const iterator. tried that:

#include<iostream> #include<set>  typedef std::set<int>::iterator it;  std::set<int> set_int;  int main() {      set_int.insert(1);     = set_int.begin();     *i = 11;  //error: assignment of read-only location }

and failed. why did fail?

according standard n4431 §23.2.4/6 associative containers [associative.reqmts] (emphasis mine):

iterator of associative container of bidirectional iterator category. for associative containers value type same key type, both iterator , const_iterator constant iterators. unspecified whether or not iterator , const_iterator same type. [ note: iterator , const_-iterator have identical semantics in case, , iterator convertible const_iterator. users can avoid violating 1 definition rule using const_iterator in function parameter lists.— end note ].

std::set associative container value type same key type, thus, std::set<t>::iterator constant iterator. consequently, failure you're getting justified.


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