Determine elements of first range without elements of second range by using set_difference() : set_difference « STL Algorithms Merge « C++ Tutorial

1. C++ Tutorial
2. STL Algorithms Merge
3. set_difference

/* The following code example is taken from the book
 * "The C++ Standard Library - A Tutorial and Reference"
 * by Nicolai M. Josuttis, Addison-Wesley, 1999
 *
 * (C) Copyright Nicolai M. Josuttis 1999.
 * Permission to copy, use, modify, sell and distribute this software
 * is granted provided this copyright notice appears in all copies.
 * This software is provided "as is" without express or implied
 * warranty, and with no claim as to its suitability for any purpose.
 */

#include <iostream>
#include <vector>
#include <deque>
#include <list>
#include <set>
#include <map>
#include <string>
#include <algorithm>
#include <iterator>
#include <functional>
#include <numeric>

/* PRINT_ELEMENTS()
 * - prints optional C-string optcstr followed by
 * - all elements of the collection coll
 * - separated by spaces
 */
template <class T>
inline void PRINT_ELEMENTS (const T& coll, const char* optcstr="")
{
    typename T::const_iterator pos;

    std::cout << optcstr;
    for (pos=coll.begin(); pos!=coll.end(); ++pos) {
        std::cout << *pos << ' ';
    }
    std::cout << std::endl;
}

/* INSERT_ELEMENTS (collection, first, last)
 * - fill values from first to last into the collection
 * - NOTE: NO half-open range
 */
template <class T>
inline void INSERT_ELEMENTS (T& coll, int first, int last)
{
    for (int i=first; i<=last; ++i) {
        coll.insert(coll.end(),i);
    }
}

using namespace std;

int main()
{
    int c1[] = { 1, 2, 2, 4, 6, 7, 7, 9 };
    int num1 = sizeof(c1) / sizeof(int);

    int c2[] = { 2, 2, 2, 3, 6, 6, 8, 9 };
    int num2 = sizeof(c2) / sizeof(int);

    // print source ranges
    cout << "c1:                         " ;
    copy (c1, c1+num1, ostream_iterator<int>(cout," "));
    cout << endl;
    cout << "c2:                         " ;
    copy (c2, c2+num2, ostream_iterator<int>(cout," "));
    cout << '\n' << endl;

    // determine elements of first range without elements of second range by using set_difference()
    cout << "set_difference():           ";
    set_difference (c1, c1+num1, c2, c2+num2, ostream_iterator<int>(cout," "));

    cout << endl;
}

c1:                         1 2 2 4 6 7 7 9
c2:                         2 2 2 3 6 6 8 9

set_difference():           1 4 7 7