c++ - Remove duplicates in string algorithm -

my homework remove duplicates in random string. idea use 2 loops solve problem.

1st 1 scan every character in string. 2nd 1 check character duplicated or not. if so, remove character.

string content = "blah blah..."      (int = 0; < content.size(); ++i) {             char check = content.at(i);             (int j = + 1; j < content.size() - 1; ++j) {                 if (check == content.at(j)) {                     content.erase(content.begin()+j);                  }             }         } 

the problem doesn't work. removes wrong character. seems indices problem don't understand why.

a temporary fix change content.erase(content.begin()+j); content.erase( remove(content.begin() + i+1, content.end(), check),content.end());

but think trigger "remove value" scan isn't nice way. want 2 loops or fewer.

any ideas appreciated :)

your loops following way

#include <iostream> #include <string>  int main()  {     std::string s = "blah blah...";      std::cout << '\"' << s << '\"' << std::endl;      ( std::string::size_type = 0; < s.size(); i++ )     {         std::string::size_type j = + 1;         while ( j < s.size() )         {             if ( s[i] == s[j] )             {                 s.erase( j, 1 );             }             else             {                 ++j;             }         }     }      std::cout << '\"' << s << '\"' << std::endl;      return 0; } 

the output is

"blah blah..." "blah b." 

there many other approaches using standard algorithms. example

#include <iostream> #include <string> #include <algorithm> #include <iterator>  int main()  {     std::string s = "blah blah...";      std::cout << '\"' << s << '\"' << std::endl;      auto last = s.end();      ( auto first = s.begin(); first != last; ++first )     {         last = std::remove( std::next( first ), last, *first );     }      s.erase( last, s.end() );      std::cout << '\"' << s << '\"' << std::endl;      return 0; } 

the output same previous code example

"blah blah..." "blah b."