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Difference between revisions of "cpp/algorithm/includes"

From cppreference.com
< cpp‎ | algorithm
m (r2.7.3) (Robot: Adding ru:cpp/algorithm/includes)
(added example)
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{{ddcl list end}}
 
{{ddcl list end}}
  
−
Returns {{c|true}} if every element from the sorted range {{tt|[first2, last2)}} is found within the sorted range {{tt|[first, last)}}. Also returns {{c|true}} if {{tt|[first2, last2)}} is empty. The first version expects both ranges to be sorted with {{c|operator<}}, the second version expects them to be sorted with the given comparison function {{tt|comp}}.
+
Returns {{c|true}} if every element from the sorted range {{tt|[first2, last2)}} is found within the sorted range {{tt|[first, last)}}. Also returns {{c|true}} if {{tt|[first2, last2)}} is empty.  
 +
 
 +
The first version expects both ranges to be sorted with {{c|operator<}}, the second version expects them to be sorted with the given comparison function {{tt|comp}}.
  
 
===Parameters===
 
===Parameters===
Line 68: Line 70:
 
  |
 
  |
 
  | code=
 
  | code=
 +
#include <iostream>
 +
#include <algorithm>
  
−
| output=
+
int main() {
 +
  std::vector<char> v1 {'a', 'b', 'c', 'f', 'h', 'x'};
 +
  std::vector<char> v2 {'a', 'b', 'c'};
 +
  std::vector<char> v3 {'a', 'c'};
 +
  std::vector<char> v4 {'g'};
 +
  std::vector<char> v5 {'a', 'c', 'g'};
 +
  std::vector<char> v6;
  
 +
  for (auto i : v1) std::cout << i << ' ';
 +
  std::cout << "includes:\n";
 +
 +
  for (auto i : v2) std::cout << i << ' ';
 +
  std::cout << ": " << std::includes(v1.begin(), v1.end(), v2.begin(), v2.end()) << '\n';
 +
  for (auto i : v3) std::cout << i << ' ';
 +
  std::cout << ": " << std::includes(v1.begin(), v1.end(), v3.begin(), v3.end()) << '\n';
 +
  for (auto i : v4) std::cout << i << ' ';
 +
  std::cout << ": " << std::includes(v1.begin(), v1.end(), v4.begin(), v4.end()) << '\n';
 +
  for (auto i : v5) std::cout << i << ' ';
 +
  std::cout << ": " << std::includes(v1.begin(), v1.end(), v5.begin(), v5.end()) << '\n';
 +
  for (auto i : v6) std::cout << i << ' ';
 +
  std::cout << ": " << std::includes(v1.begin(), v1.end(), v6.begin(), v6.end()) << '\n';
 +
 +
  std::vector<char> v7 {'A', 'B', 'C'};
 +
  for (auto i : v7) std::cout << i << ' ';
 +
  std::cout << ": "
 +
            << std::includes(v1.begin(), v1.end(), v7.begin(), v7.end(),
 +
                            [](char a, char b) { return tolower(a) < tolower(b); })
 +
            << '\n';
 +
}
 +
| output=
 +
a b c f h x includes:
 +
a b c : 1
 +
a c : 1
 +
g : 0
 +
a c g : 0
 +
A B C : 1
 
}}
 
}}
  

Revision as of 05:45, 21 May 2012

Template:cpp/algorithm/sidebar Template:ddcl list begin <tr class="t-dsc-header">

<td>
Defined in header <algorithm>
</td>

<td></td> <td></td> </tr> <tr class="t-dcl ">

<td >
template< class InputIterator1, class InputIterator2 >

bool includes( InputIterator1 first1, InputIterator1 last1,

               InputIterator2 first2, InputIterator2 last2 );
</td>

<td > (1) </td> <td class="t-dcl-nopad"> </td> </tr> <tr class="t-dcl ">

<td >
template< class InputIterator1, class InputIterator2 >

bool includes( InputIterator1 first1, InputIterator1 last1,

               InputIterator2 first2, InputIterator2 last2, Compare comp );
</td>

<td > (2) </td> <td class="t-dcl-nopad"> </td> </tr> Template:ddcl list end

Returns true if every element from the sorted range [first2, last2) is found within the sorted range [first, last). Also returns true if [first2, last2) is empty.

The first version expects both ranges to be sorted with operator<, the second version expects them to be sorted with the given comparison function comp.

Contents

Parameters

first1, last1 - the range of elements to examine
first2, last2 - the range of elements to search for
comp - comparison function object (i.e. an object that satisfies the requirements of Compare) which returns true if the first argument is less than the second.

The signature of the comparison function should be equivalent to the following:

bool cmp(const Type1& a, const Type2& b);

While the signature does not need to have const&, the function must not modify the objects passed to it and must be able to accept all values of type (possibly const) Type1 and Type2 regardless of value category (thus, Type1& is not allowed, nor is Type1 unless for Type1 a move is equivalent to a copy(since C++11)).
The types Type1 and Type2 must be such that an object of type InputIterator can be dereferenced and then implicitly converted to both of them.

Return value

true if every element from [first2, last2) is a member of [first, last).

Complexity

At most 2·(N1+N2-1) comparisons, where N1 = std::distance(first1, last1) and N2 = std::distance(first2, last2).

Possible implementation

Template:eq fun cpp

Example

Run this code
#include <iostream>
#include <algorithm>
 
int main() {
  std::vector<char> v1 {'a', 'b', 'c', 'f', 'h', 'x'};
  std::vector<char> v2 {'a', 'b', 'c'};
  std::vector<char> v3 {'a', 'c'};
  std::vector<char> v4 {'g'};
  std::vector<char> v5 {'a', 'c', 'g'};
  std::vector<char> v6;
 
  for (auto i : v1) std::cout << i << ' ';
  std::cout << "includes:\n";
 
  for (auto i : v2) std::cout << i << ' ';
  std::cout << ": " << std::includes(v1.begin(), v1.end(), v2.begin(), v2.end()) << '\n';
  for (auto i : v3) std::cout << i << ' ';
  std::cout << ": " << std::includes(v1.begin(), v1.end(), v3.begin(), v3.end()) << '\n';
  for (auto i : v4) std::cout << i << ' ';
  std::cout << ": " << std::includes(v1.begin(), v1.end(), v4.begin(), v4.end()) << '\n';
  for (auto i : v5) std::cout << i << ' ';
  std::cout << ": " << std::includes(v1.begin(), v1.end(), v5.begin(), v5.end()) << '\n';
  for (auto i : v6) std::cout << i << ' ';
  std::cout << ": " << std::includes(v1.begin(), v1.end(), v6.begin(), v6.end()) << '\n';
 
  std::vector<char> v7 {'A', 'B', 'C'};
  for (auto i : v7) std::cout << i << ' ';
  std::cout << ": "
            << std::includes(v1.begin(), v1.end(), v7.begin(), v7.end(),
                             [](char a, char b) { return tolower(a) < tolower(b); })
            << '\n';
}

Output: 

a b c f h x includes:
a b c : 1
a c : 1
g : 0
a c g : 0
A B C : 1

See also

Template:cpp/algorithm/dcl list set difference
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