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      std::list<T,Allocator>::erase

      From cppreference.com
      <cpp‎ |container‎ |list

      [edit template]
       
       
       
      std::list
      Member functions
      Non-member functions
      (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)
      Deduction guides(C++17)
       
      (1)
      iterator erase( iterator pos);
      (until C++11)
      iterator erase( const_iterator pos);
      (since C++11)
      (constexpr since C++26)
      (2)
      iterator erase( iterator first, iterator last);
      (until C++11)
      iterator erase( const_iterator first, const_iterator last);
      (since C++11)
      (constexpr since C++26)

      Erases the specified elements from the container.

      1) Removes the element atpos.
      2) Removes the elements in the range[firstlast).

      References and iterators to the erased elements are invalidated. Other references and iterators are not affected.

      The iteratorpos must be valid and dereferenceable. Thus theend() iterator (which is valid, but is not dereferenceable) cannot be used as a value forpos.

      The iteratorfirst does not need to be dereferenceable iffirst== last: erasing an empty range is a no-op.

      Contents

      [edit]Parameters

      pos - iterator to the element to remove
      first, last - the pair of iterators defining therange of elements to remove

      [edit]Return value

      Iterator following the last removed element.

      1) Ifpos refers to the last element, then theend() iterator is returned.
      2) Iflast== end() prior to removal, then the updatedend() iterator is returned.
      If[firstlast) is an empty range, thenlast is returned.

      [edit]Complexity

      1) Constant.
      2) Linear in the distance betweenfirst andlast.

      [edit]Notes

      When container elements need to be erased based on a predicate, rather than iterating the container and calling unaryerase, the iterator range overload is generally used withstd::remove()/std::remove_if() to minimise the number of moves of the remaining (non-removed) elements, — this is the erase-remove idiom.std::erase_if() replaces the erase-remove idiom.(since C++20)

      [edit]Example

      Run this code
      #include <list>#include <iostream>#include <iterator> void print_container(conststd::list<int>& c){for(int i: c)std::cout<< i<<' ';std::cout<<'\n';} int main(){std::list<int> c{0,1,2,3,4,5,6,7,8,9};    print_container(c);     c.erase(c.begin());    print_container(c); std::list<int>::iterator range_begin= c.begin();std::list<int>::iterator range_end= c.begin();std::advance(range_begin,2);std::advance(range_end,5);     c.erase(range_begin, range_end);    print_container(c); // Erase all even numbersfor(std::list<int>::iterator it= c.begin(); it!= c.end();){if(*it%2==0)            it= c.erase(it);else++it;}    print_container(c);}

      Output:

      0 1 2 3 4 5 6 7 8 91 2 3 4 5 6 7 8 91 2 6 7 8 91 7 9

      Defect reports

      The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

      DRApplied toBehavior as publishedCorrect behavior
      LWG 151C++98first was required to be dereferenceable, which
      made the behavior of clearing an emptylist undefined
      not required if
      first== last

      [edit]See also

      erases all elements satisfying specific criteria
      (function template)[edit]
      clears the contents
      (public member function)[edit]
      Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/container/list/erase&oldid=135233"

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