Поменять местами первое и последнее слово, найти слова-палиндромы

#ifndef SENTENCE_H_
#define SENTENCE_H_
 
#include <string>
#include <vector>
#include <ostream>
 
class Sentence {
private:
    std::vector<std::string> words;
public:
    Sentence(const std::string & str);
    void swapHeadTail();
    bool isPalindrome(const std::string & s) const;
    std::vector<std::string> innerPalindromes() const;
    friend std::ostream & operator << (std::ostream & ost, const Sentence & sent);
};
 
#endif /* SENTENCE_H_ */

#include "sentence.h"
#include <algorithm>
#include <iterator>
#include <functional>
#include <sstream>
 
Sentence::Sentence(const std::string & str) {
    std::istringstream ist(str);
    std::copy(std::istream_iterator<std::string>(ist), std::istream_iterator<std::string>(), std::back_inserter(words));
}
 
void Sentence::swapHeadTail() {
    std::swap(*words.begin(), *words.rbegin());
}
 
bool Sentence::isPalindrome(const std::string & str) const {
    std::string rst = str;
    std::reverse(rst.begin(), rst.end());
 
    return ( rst == str);
}
 
std::vector<std::string> Sentence::innerPalindromes() const {
    std::vector<std::string> ip;
    for ( std::vector<std::string>::const_iterator i = words.begin(); i != words.end(); ++i )
        if ( isPalindrome(*i) )
            ip.push_back(*i);
 
    return ip;
}
 
std::ostream & operator << (std::ostream & ost, const Sentence & sent) {
    std::copy(sent.words.begin(), sent.words.end(), std::ostream_iterator<std::string>(ost, " "));
    return ost;
}

#include "sentence.h"
#include <iostream>
#include <iterator>
 
int main() {
    Sentence sent("any 12321 many 4554 money more");
 
    std::cout << "Sentence: " << sent << std::endl;
 
    std::vector<std::string> palindromes = sent.innerPalindromes();
    if ( ! palindromes.empty() ) {
        std::cout << "Inner palindromes: ";
        std::copy(palindromes.begin(), palindromes.end(), std::ostream_iterator<std::string>(std::cout, " "));
        std::cout << std::endl;
    }
    else
        std::cout << "No inner palindromes found!" << std::endl;
 
    sent.swapHeadTail();
    std::cout << "Swap head & tail: " << sent << std::endl;
    std::cout << "bla bla bla" << " is" << ( ( sent.isPalindrome("bla bla bla") ) ? " " : " not " ) << "a palindrome." << std::endl;
    std::cout << "abc cba" << " is" << ( ( sent.isPalindrome("abc cba") ) ? " " : " not " ) << "a palindrome." << std::endl;
 
    return 0;
}