Удаление элементов из вектора

string f="/.+(STL).$1/";
   vector<string> words;
   words.push_back(f);
   vector< string >::iterator first = find( words. begin(), words.end(), "+" );
   vector< string >::iterator last =find( words. begin(), words.end(), "1" );
 words.erase(first,last);

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
using namespace std;
int main()
{
    setlocale (LC_CTYPE,"rus");
    
   string f="/.+(STL).$1/";
   vector<string> words;
   words.push_back(f);
   vector< string >::iterator first = find( words. begin(), words.end(), "+" );
   vector< string >::iterator last =find( words. begin(), words.end(), "1" );
 words.erase(first,last);
    
   
    for(vector<string>::iterator ix=words.begin();ix!=words.end();++ix)
    {
        cout<<endl<<(*ix);
    }
 
    system("pause");
    return 0;
}

#include <iostream>
#include <string>
using namespace std;
void eraseSumbInStr(string& toCrack, string::size_type posit){
 if(toCrack.size()>posit) toCrack.erase(posit,1);
 else
cout<<"someting wrong with the string "<<toCrack<<" \nat function \"void eraseSumbInStr(string& toCrack, string::size_type posit)\" "<<endl;
}
int main()
{
    string f="/.+(STL).$1/";
   cout<<f;
   string::size_type first = f.find_first_of("+");
   string::size_type last = f.find_first_of("l");//не найдёт
   cout<<endl;
   cout<<first<<" "<<last<<endl;
   eraseSumbInStr(f, first);
   eraseSumbInStr(f, last);
   cout<<f<<endl;
    cin.get();
    return 0;
}

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
using namespace std;
typedef vector<char>::iterator chit;
int main()
{
    vector<char> words;
    string f="/.+(STL).$1/";
  for (unsigned i=0; i<f.length(); i++)
  {   words.push_back( f.at(i));   }
 for(chit ix=words.begin();ix!=words.end();++ix)
{
    if ((*ix)!='S' && (*ix)!='T' && (*ix)!='L' || (*ix)=='.')
    {
      words.erase(ix);
      ix=words.begin();
    }
}
    for(chit iy=words.begin();iy!=words.end();++iy)
    {        cout<<(*iy)<<endl;   }
 return 0;
}

#include<string>
#include<iostream>
 
int main(){
    std::string str="/.+(STL).$1/";
    std::string findStr = "STL";
    size_t pos = str.find(findStr);
    if(pos != std::string::npos){
        str.erase(0,pos);
        str.erase(str.begin()+findStr.size(),str.end());
    }else{
        str.clear();
    }
    std::cout<<str<<std::endl;
}

for(chit ix=words.begin(); ix!=words.end(); )
{
    if ((*ix)!='S' && (*ix)!='T' && (*ix)!='L')
        ix = words.erase(ix);
    else
        ++ix;
}

iterator erase (const_iterator position);
iterator erase (const_iterator first, const_iterator last);

string f("/.+(STL).$1/");
vector<char> words(f.begin(), f.end());