|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
basic_string& erase( size_type index=0, size_type count= npos); | (1) | (constexpr since C++20) |
| (2) | ||
iterator erase( iterator position); | (until C++11) | |
iterator erase( const_iterator position); | (since C++11) (constexpr since C++20) | |
| (3) | ||
iterator erase( iterator first, iterator last); | (until C++11) | |
iterator erase( const_iterator first, const_iterator last); | (since C++11) (constexpr since C++20) | |
Removes specified characters from the string.
[first, last).[first, last) is not avalid range, the behavior is undefined.Contents |
| index | - | first character to remove |
| count | - | number of characters to remove |
| position | - | iterator to the character to remove |
| first, last | - | range of the characters to remove |
If an exception is thrown for any reason, this function has no effect (strong exception safety guarantee).
#include <algorithm>#include <iostream>#include <iterator>#include <string> int main(){std::string s="This Is An Example";std::cout<<"1) "<< s<<'\n'; s.erase(7,3);// erases " An" using overload (1)std::cout<<"2) "<< s<<'\n'; s.erase(std::find(s.begin(), s.end(),' '));// erases first ' '; overload (2)std::cout<<"3) "<< s<<'\n'; s.erase(s.find(' '));// trims from ' ' to the end of the string; overload (1)std::cout<<"4) "<< s<<'\n'; auto it=std::next(s.begin(), s.find('s'));// obtains iterator to the first 's' s.erase(it,std::next(it,2));// erases "sI"; overload (3)std::cout<<"5) "<< s<<'\n';}
Output:
1) This Is An Example2) This Is Example3) ThisIs Example4) ThisIs5) This
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 27 | C++98 | overload(3) did not erase the characterlast pointed to, but it returned the iterator pointing to the character immediately following that character | returns an iterator pointing to that character |
| LWG 428 | C++98 | overload(2) explicitly requiredposition to be valid, but SequenceContainer requires it to be dereferenceable (stricter) | removed the explicit requirement |
| LWG 847 | C++98 | there was no exception safety guarantee | added strong exception safety guarantee |
| clears the contents (public member function)[edit] |
