Sets Stl C++ Code Example

Example 1: set in c++

#include <bits/stdc++.h> #include <iostream> #include <vector> #include <algorithm> #include <set>  using namespace std; //set mentains internally the ascending order of these numbers void setDemo() { 	set<int> S; 	S.insert(1); 	S.insert(2); 	S.insert(-1); 	S.insert(-10); 	S.erase(1);//to remove an element 	 	//Print all the values of the set in ascending order 	for(int x:S){ 		cout<<x<<" "; 	} 	 	//check whether an element is present in a set or not 	auto it = S.find(-1);//this will return an iterator to -1 	//if not present it will return an iterator to S.end() 	 	if (it == S.end()){ 		cout<<"not Present\n"; 	}else{ 		cout <<" present\n"; 		cout << *it <<endl; 	} 	//iterator to the first element in the set which is 	//greater than or equal to -1 	auto it2 = S.lower_bound(-1); 	//for strictly greater than -1 	auto it3 = S.upper_bound(-1); 	//print the contents of both the iterators 	cout<<*it2<<" "<<*it3<<endl; } 	 int main() { 	setDemo(); 	return 0; }

Example 2: set c++

// constructing sets #include <iostream> #include <set>  bool fncomp (int lhs, int rhs) {return lhs<rhs;}  struct classcomp {   bool operator() (const int& lhs, const int& rhs) const   {return lhs<rhs;} };  int main () {   std::set<int> first;                           // empty set of ints    int myints[]= {10,20,30,40,50};   std::set<int> second (myints,myints+5);        // range    std::set<int> third (second);                  // a copy of second    std::set<int> fourth (second.begin(), second.end());  // iterator ctor.    std::set<int,classcomp> fifth;                 // class as Compare    bool(*fn_pt)(int,int) = fncomp;   std::set<int,bool(*)(int,int)> sixth (fn_pt);  // function pointer as Compare    return 0; }