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Returns whether each element of a range is also an element of another range

### Key Facts

**Gyroscopic Couple**: The rate of change of angular momentum () = (In the limit).

- = Moment of Inertia.
- = Angular velocity
- = Angular velocity of precession.

**Blaise Pascal**(1623-1662) was a French mathematician, physicist, inventor, writer and Catholic philosopher.

**Leonhard Euler**(1707-1783) was a pioneering Swiss mathematician and physicist.

## Definition

The**includes()**algorithm is defined in the standard header

**<algorithm>**and in the nonstandard backward-compatibility header

**<algo.h>**.

## Interface

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

**Parameters:**

Parameter | Description |
---|---|

first1 | An input iterator addressing the position of the first element in the first of two sorted source ranges to be tested for whether all the elements of the second are contained in the first |

last1 | An input iterator addressing the position one past the last element in the first of two sorted source ranges to be tested for whether all the elements of the second are contained in the first |

first2 | An input iterator addressing the position of the first element in second of two consecutive sorted source ranges to be tested for whether all the elements of the second are contained in the first |

last2 | An input iterator addressing the position one past the last element in second of two consecutive sorted source ranges to be tested for whether all the elements of the second are contained in the first |

comp | User-defined predicate function object that defines sense in which one element is less than another. A binary predicate takes two arguments and returns `true` when satisfied and `false` when not satisfied |

## Description

**Includes**function tests if one sorted range (

`[first2, last2)`

) contains all the elements contained in a second sorted range (`[first1, last1)`

), where the ordering or equivalence criterion between elements may be specified by a binary predicate.
The first version compares objects using `operator<`

, and the second compares objects using a function object `comp`

.## Return Value

Returns**true**if every element from

`[first2, last2)`

is a member of `[first1, last1)`

, otherwise returns **false**.

## Complexity

The complexity is**linear;**performs at most

`2 * ((last1 - first1) + (last2 - first2)) - 1`

comparisons.Example:

##### Example - includes algorithm

Problem

This program illustrates the use of the STL

**includes()**algorithm (default version) to test whether the values in a second (sorted) range of integer values in a vector of integers are all present in a first (sorted) range of integer values, also in a vector of integers.Workings

#include <iostream> #include <vector> #include <algorithm> using namespace std; int main() { int a1[] = {1, 2, 4, 8, 16, 32, 64, 128, 256, 512}; vector<int> v1(a1, a1+10); cout <<"\nHere are the contents of v1:\n"; for (vector<int>::size_type i=0; i<v1.size(); i++) cout <<v1.at(i)<<" "; int a2[] = {2, 16, 128, 512}; vector<int> v2(a2, a2+4); cout <<"\nHere are the contents of v2:\n"; for (vector<int>::size_type i=0; i<v2.size(); i++) cout <<v2.at(i)<<" "; if (includes(v1.begin(), v1.end(), v2.begin(), v2.end())) cout <<"\nv1 includes v2."; else cout <<"\nv1 does not include v2."; int a3[] = {2, 16, 128, 1024}; vector<int> v3(a3, a3+4); cout <<"\nHere are the contents of v3:\n"; for (vector<int>::size_type i=0; i<v3.size(); i++) cout <<v3.at(i)<<" "; if (includes(v1.begin(), v1.end(), v3.begin(), v3.end())) cout <<"\nv1 includes v3."; else cout <<"\nv1 does not include v3."; return 0; }

Solution

**Output:**Here are the contents of v1:

1 2 4 8 16 32 64 128 256 512 Here are the contents of v2:

2 16 128 512 v1 includes v2. Here are the contents of v3:

2 16 128 1024 v1 does not include v3.

References