c++ set intersection
To find the intersection of two sets in C++, you can use the std::set_intersection algorithm from the <algorithm> library. Here are the steps to perform a set intersection in C++:
- Include the necessary libraries: Begin by including the necessary libraries for working with sets and algorithms in C++.
cpp
#include <iostream>
#include <algorithm>
#include <set>
- Create the sets: Define and populate two sets with the desired elements.
cpp
std::set<int> set1 = {1, 2, 3, 4, 5};
std::set<int> set2 = {4, 5, 6, 7, 8};
- Create a third set: Create an empty set to store the intersection of the two sets.
cpp
std::set<int> intersectionSet;
- Perform the set intersection: Use the
std::set_intersectionalgorithm to find the common elements between the two sets. This algorithm requires the sets to be sorted, so you can use thestd::sortfunction to sort the sets if they are not already sorted.
```cpp std::sort(set1.begin(), set1.end()); std::sort(set2.begin(), set2.end());
std::set_intersection(set1.begin(), set1.end(), set2.begin(), set2.end(), std::inserter(intersectionSet, intersectionSet.begin()); ```
The std::set_intersection algorithm takes the following parameters:
- set1.begin() and set1.end(): The iterators defining the range of the first set.
- set2.begin() and set2.end(): The iterators defining the range of the second set.
- std::inserter(intersectionSet, intersectionSet.begin()): An iterator that represents the position where the intersection elements will be inserted into the intersectionSet.
- Print the intersection: Finally, you can iterate over the
intersectionSetand print its elements to see the intersection.
cpp
for (const auto& element : intersectionSet) {
std::cout << element << " ";
}
This will output: 4 5, which are the elements common to both set1 and set2.
And that's it! You have successfully performed a set intersection in C++ using the std::set_intersection algorithm.