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==Container includes: generic includes algorithm==

<source lang="cpp">

#include <iostream>
#include <cassert>
#include <algorithm>
#include <vector>
using namespace std;
int main()
{
bool result;
string s("abcde");
string s2("aeiou");
vector<char> vector1(s.begin(), s.end());
vector<char> vector2(s2.begin(), s2.end());
// Illustrate includes:
result = includes(vector1.begin(), vector1.end(),vector2.begin(), vector2.end());
assert (result == false);
result = includes(vector1.begin(), vector1.end(),vector2.begin(), vector2.begin() + 2);
// "a" and "e" are contained in vector1
assert (result == true);
return 0;
}

</source>

==Determine whether one set is completely contained in another set==

<source lang="cpp">

#include <iostream>
using std::cout;
using std::endl;
#include <algorithm>
#include <iterator>
int main()
{
const int SIZE1 = 10, SIZE2 = 5, SIZE3 = 20;
int a1[ SIZE1 ] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
int a2[ SIZE2 ] = { 4, 5, 6, 7, 8 };
int a3[ SIZE2 ] = { 4, 5, 6, 11, 15 };
std::ostream_iterator< int > output( cout, " " );
std::copy( a1, a1 + SIZE1, output );
cout << "\n";
std::copy( a2, a2 + SIZE2, output );
cout << "\n";
std::copy( a3, a3 + SIZE2, output );
if ( std::includes( a1, a1 + SIZE1, a2, a2 + SIZE2 ) )
cout << "\n\na1 includes a2";
else
cout << "\n\na1 does not include a2";
return 0;
}
/*
1 2 3 4 5 6 7 8 9 10
4 5 6 7 8
4 5 6 11 15
a1 includes a2
*/

</source>

==Use includes and search to check whether all elements in search are also in coll==

<source lang="cpp">

/* 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()
{
list<int> coll;
vector<int> search;
INSERT_ELEMENTS(coll,1,9);
PRINT_ELEMENTS(coll,"coll: ");
search.push_back(3);
search.push_back(4);
search.push_back(7);
PRINT_ELEMENTS(search,"search: ");
// check whether all elements in search are also in coll
if (includes (coll.begin(), coll.end(),
search.begin(), search.end())) {
cout << "all elements of search are also in coll"
<< endl;
}
else {
cout << "not all elements of search are also in coll"
<< endl;
}
}
/*
coll: 1 2 3 4 5 6 7 8 9
search: 3 4 7
all elements of search are also in coll
*/

</source>

==Use includes() function to check if one set contains another set==

<source lang="cpp">
#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;

void print(int elem) {
cout << elem << " ";
}
int main(int argc, char** argv) {
vector<int> setOne, setTwo, setThree;
setOne.push_back(1);
setOne.push_back(2);
setOne.push_back(3);

setTwo.push_back(2);
setTwo.push_back(3);
setTwo.push_back(4);
// set algorithms work on sorted ranges
sort(setOne.begin(), setOne.end());
sort(setTwo.begin(), setTwo.end());
if (includes(setOne.begin(), setOne.end(), setTwo.begin(), setTwo.end())) {
cout << "The second set is a subset of the first\n";
}
if (includes(setTwo.begin(), setTwo.end(), setOne.begin(), setOne.end())) {
cout << "The first set is a subset of the second\n";
}
return (0);
}

</source>

==Use includes() to check for subset==

<source lang="cpp">
#include <iostream>
#include <list>
#include <algorithm>
using namespace std;
template<class InIter>
void show_range(const char *msg, InIter start, InIter end);
int main()
{
list<char> list1, list2, result(15), list3;
list<char>::iterator res_end;
for(int i=0; i < 5; i++)
list1.push_back("A"+i);
for(int i=3; i < 10; i++)
list2.push_back("A"+i);

show_range("Contents of list1: ", list1.begin(), list1.end());
list3.push_back("A");
list3.push_back("C");
list3.push_back("D");

if(includes(list1.begin(), list1.end(),list3.begin(), list3.end()))
cout << "list3 is a subset of list1" << endl;
else
cout << "list3 is not a subset of list1" << endl;
return 0;
}
template<class InIter>
void show_range(const char *msg, InIter start, InIter end) {
InIter itr;
cout << msg << endl;
for(itr = start; itr != end; ++itr)
cout << *itr << endl;
}

</source>

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