## includes

    Algorithm

- Summary
- Data Type and Member Function Indexes
- Synopsis
- Description
- Complexity
- Example
- Warnings
- See Also

### Summary

A basic set of operation for sorted sequences.

### Data Type and Member Function Indexes
(exclusive of constructors and destructors)

None

### Synopsis

    #include <algorithm>
    template <class InputIterator1, class InputIterator2>
     bool includes (InputIterator1 first1, InputIterator1 last1,
                    InputIterator2 first2,
                    InputIterator2 last2);

    template <class InputIterator1, class InputIterator2,
              class Compare>
     bool includes (InputIterator1 first1, InputIterator1 last1,
                  InputIterator2 first2,
                  InputIterator2 last2, Compare comp);

### Description

The includes algorithm compares two sorted sequences and returns `true` if every element in the range `[first2, last2)` is contained in the range `[first1, last1)`. It returns `false` otherwise. include assumes that the sequences are sorted using the less than operator (`operator<`), unless an alternative comparison operator (`comp`) is included.

### Complexity

At most `((last1 - first1) + (last2 - first2)) * 2 -1` comparisons are performed.

### Example

    //
    // includes.cpp
    //
     #include <algorithm>
     #include <set>
     #include <iostream>
     using namespace std;

     int main()
     {

       //Initialize some sets
       int a1[10] = {1,2,3,4,5,6,7,8,9,10};
       int a2[6]  = {2,4,6,8,10,12};
       int a3[4]  = {3,5,7,8};
       set<int, less<int> > all(a1, a1+10), even(a2, a2+6),
                             small(a3,a3+4);

      //Demonstrate includes
      cout << "The set: ";
      copy(all.begin(),all.end(),
            ostream_iterator<int,char>(cout," "));
      bool answer = includes(all.begin(), all.end(),
                    small.begin(), small.end());
      cout << endl
           << (answer ? "INCLUDES " : "DOES NOT INCLUDE ");
      copy(small.begin(),small.end(),
            ostream_iterator<int,char>(cout," "));
      answer = includes(all.begin(), all.end(),
                        even.begin(), even.end());
      cout << ", and" << endl
           << (answer ? "INCLUDES" : "DOES NOT INCLUDE ");
      copy(even.begin(),even.end(),
            ostream_iterator<int,char>(cout," "));
      cout << endl << endl;

      return 0;
     }

Program Output

    The set: 1 2 3 4 5 6 7 8 9 10
    INCLUDES 3 5 7 8 , and
    DOES NOT INCLUDE 2 4 6 8 10 12

### Warnings

If your compiler does not support default template parameters, then you always need to supply the `Allocator` template argument. For instance, you have to write:

`set<int, less<int>, allocator<int> >`

instead of:

`set<int>`

If your compiler does not support namespaces, then you do not need the using declaration for `std`.

### See Also

set,set_union, set_intersection, set_difference, set_symmetric_difference

Copyright (c) 1998, Rogue Wave Software, Inc.
Send mail to report errors or comment on the documentation.
OEM Release, June 1998