In this shot, we will learn how to use the set_intersection()
function in C++.
The set_intersection()
function is available in the <algorithm>
library in C++.
The set_intersection()
function is used to find the intersection of the two sorted ranges, which is formed only by the common elements between the sets.
The syntax of the set_intersection()
function is shown below:
OutputIterator set_intersection(first1, last1, first2, last2, res)
The set_intersection()
method takes the following parameters:
The set_intersection()
returns an iterator to the end of the constructed range.
Let’s have a look at the code now.
#include <algorithm> #include <iostream> #include <vector> using namespace std; int main() { int first[] = { 25, 110, 105, 120, 125 }; int second[] = { 150, 120, 105, 225, 25 }; int n = sizeof(first) / sizeof(first[0]); cout << "First array contains :"; for (int i = 0; i < n; i++) cout << " " << first[i]; cout << "\n"; cout << "Second array contains :"; for (int i = 0; i < n; i++) cout << " " << second[i]; cout << "\n\n"; vector<int> vec(10); vector<int>::iterator it1, st1; sort(first, first + n); sort(second, second + n); it1 = set_intersection(first, first + n, second, second + n, vec.begin()); cout << "The intersection has " << (it1 - vec.begin())<< " elements:\n"; for (st1 = vec.begin(); st1 != it1; ++st1) cout << ' ' << *st1; cout << '\n'; return 0; }
In lines 1 to 3, we imported the required header files.
In line 6, we made a main()
function.
In line 9 and 10, we initialized two arrays.
From lines 13 to 15, we displayed the elements of the first array.
From lines 18 to 20, we displayed the elements of the second array.
In line 23, we declared a vector of int
type.
In line 24, we declared two iterators to a vector of int
type.
In lines 26 and 27, we sorted the two arrays.
In line 29, we used the set_intersection()
function to obtain the intersection and store the output vector’s initial position in the iterator.
In line 31, we displayed the number of elements in the intersection.
In lines 32 and 33, we displayed the elements of intersection using the iterator and loop.
So, this is how to use the set_intersection()
function in C++.
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