set comparator c++ code example

Example 1: c++ custom comparator for elements in set

struct compare {
    bool operator() (const int& x, const int& y) const {
        return x<y; // if x<y then x will come before y. Change this condition as per requirement
    }
};
int main()
{
  set<int,compare> s; //use the comparator like this
}

Example 2: reverse iterator c++

// A reverse_iterator example using vectors

#include <iostream>
#include <vector>

int main() {
	std::vector<int> vec = {1, 2, 3, 4, 5};
  	std::vector<int>::reverse_iterator r_iter;
  
    // rbegin() points to the end of the vector, and rend()
    // points to the front. Use crbegin() and crend() for
  	// the const versions of these interators.
    for (r_iter = vec.rbegin(); r_iter != vec.rend(); r_iter++) {
        std::cout << *r_iter << std::endl;
    }
  	
  	return 0;
}