util.h

#ifndef UTIL_H
#define UTIL_H
#include <string>
#include <iostream>
#include <set>


/** Complete the setIntersection and setUnion functions below
 *  in this header file (since they are templates).
 *  Both functions should run in time O(n*log(n)) and not O(n^2)
 */
template <typename T>
std::set<T> setIntersection(const std::set<T>& s1, std::set<T>& s2)
{
typename std::set <T> shared; 
//returns same values in two sets as a set 
for(typename std::set <T>:: iterator it =s1.begin(); it != s1.end(); ++it){
    if(s2.find(*it)!=s2.end()){
        shared.insert(*it);
    }
}
return shared;

}
template <typename T>
std::set<T> setUnion(const std::set<T>& s1, std::set<T>& s2)
{
//returns a set of all words in sets
std::set <T> allwords;
for(typename std::set <T>:: iterator it1 =s1.begin(); it1 !=s1.end(); ++it1){
    allwords.insert(*it1);
}
for(typename std::set <T>:: iterator it2 =s2.begin(); it2 !=s2.end(); ++it2){
    allwords.insert(*it2);
}
return allwords;
}

/***********************************************/
/* Prototypes of functions defined in util.cpp */
/***********************************************/

std::string convToLower(std::string src);

std::set<std::string> parseStringToWords(std::string line);

// Used from http://stackoverflow.com/questions/216823/whats-the-best-way-to-trim-stdstring
// Removes any leading whitespace
std::string &ltrim(std::string &s) ;

// Removes any trailing whitespace
std::string &rtrim(std::string &s) ;

// Removes leading and trailing whitespace
std::string &trim(std::string &s) ;
#endif