#include <string>
#include <cctype>

using namespace std;


// each class here is for building function objects (functors)
// each comparison function returns true if the first parameter comes 
//  BEFORE the second parameter in the ordering, false otherwise


class LengthCompare
{
public:
   bool operator() (string s1, string s2)
   {
      return (s1.length() < s2.length());
   };
};

class AlphabeticCompare
{
public:
   bool operator() (string s1, string s2)
   {
      string x = s1;	// make copies
      string y = s2;

      for (int i = 0; i < x.length(); i++)
          x[i] = tolower(x[i]);      

      for (int i = 0; i < y.length(); i++)
          y[i] = tolower(y[i]);      

      return (x < y);
   };
};

class LastLetterCompare
{
public:
   bool operator() (string s1, string s2)
   {
      return (s1[s1.length()-1] < s2[s2.length()-1]);
   };
};