#include <algorithm>    // for std::set_difference(), std::sort()
#include <iostream>     // for std::cout, std::endl
#include <iterator>     // for std::inserter
#include <string>       // for std::string
#include <vector>       // for std::vector
using namespace std;

void print(const char* name, const vector<string>& v);

int main() 
{
    // Input vectors
    vector<string> a = {"the", "of"};
    vector<string> b = {"oranges", "the", "of", "apples"};
    
    print("a", a);
    print("b", b);

    // Sort the vectors before calling std::set_difference().
    sort(a.begin(), a.end());
    sort(b.begin(), b.end());
    
    // Resulting difference vector
    vector<string> c;
    set_difference(a.begin(), a.end(),
                   b.begin(), b.end(),
                   inserter(c, c.begin()));
                   
    print("difference(a,b)", c);
}


void print(const char* name, const vector<string>& v) 
{
    cout << name << " = {";
    bool first = true;
    for (const auto& s : v) 
    {
        if (first) 
        {
            first = false;
            cout << s;
        } 
        else 
        {
            cout << ", " << s;
        }
    }
    cout << "}" << endl;
}