set 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;
}

#include <iostream> 
#include <set> 
#include <iterator> 
  
using namespace std; 
  
int main() 
{ 
    // empty set container 
    set <int, greater <int> > s1;         
  
    // insert elements in random order 
    s1.insert(40); 
    s1.insert(30); 
    s1.insert(60); 
    s1.insert(20); 
    s1.insert(50); 
    s1.insert(50); // only one 50 will be added to the set 
    s1.insert(10); 
  
    // printing set s1 
    set <int, greater <int> > :: iterator itr; 
    cout << "\nThe set s1 is : "; 
    for (itr = s1.begin(); itr != s1.end(); ++itr) 
    { 
        cout << '\t' << *itr; 
    } 
    cout << endl; 
  
    // assigning the elements from s1 to s2 
    set <int> s2(s1.begin(), s1.end()); 
  
    // print all elements of the set s2 
    cout << "\nThe set s2 after assign from s1 is : "; 
    for (itr = s2.begin(); itr != s2.end(); ++itr) 
    { 
        cout << '\t' << *itr; 
    } 
    cout << endl; 
  
    // remove all elements up to 30 in s2 
    cout << "\ns2 after removal of elements less than 30 : "; 
    s2.erase(s2.begin(), s2.find(30)); 
    for (itr = s2.begin(); itr != s2.end(); ++itr) 
    { 
        cout << '\t' << *itr; 
    } 
  
    // remove element with value 50 in s2 
    int num; 
    num = s2.erase (50); 
    cout << "\ns2.erase(50) : "; 
    cout << num << " removed \t" ; 
    for (itr = s2.begin(); itr != s2.end(); ++itr) 
    { 
        cout << '\t' << *itr; 
    } 
  
    cout << endl; 
  
    //lower bound and upper bound for set s1 
    cout << "s1.lower_bound(40) : "
         << *s1.lower_bound(40) << endl; 
    cout << "s1.upper_bound(40) : "
         << *s1.upper_bound(40) << endl; 
  
    //lower bound and upper bound for set s2 
    cout << "s2.lower_bound(40) : "
         << *s2.lower_bound(40) << endl; 
    cout << "s2.upper_bound(40) : "
         << *s2.upper_bound(40) << endl; 
  
    return 0; 
  
} 

#include <iostream> 
#include <set> 
#include <iterator> 
  
using namespace std; 
  
int main() 
{ 
    // empty set container 
    set <int, greater <int> > gquiz1;         
  
    // insert elements in random order 
    gquiz1.insert(40); 
    gquiz1.insert(30); 
    gquiz1.insert(60); 
    gquiz1.insert(20); 
    gquiz1.insert(50); 
    gquiz1.insert(50); // only one 50 will be added to the set 
    gquiz1.insert(10); 
  
    // printing set gquiz1 
    set <int, greater <int> > :: iterator itr; 
    cout << "\nThe set gquiz1 is : "; 
    for (itr = gquiz1.begin(); itr != gquiz1.end(); ++itr) 
    { 
        cout << '\t' << *itr; 
    } 
    cout << endl; 
  
    // assigning the elements from gquiz1 to gquiz2 
    set <int> gquiz2(gquiz1.begin(), gquiz1.end()); 
  
    // print all elements of the set gquiz2 
    cout << "\nThe set gquiz2 after assign from gquiz1 is : "; 
    for (itr = gquiz2.begin(); itr != gquiz2.end(); ++itr) 
    { 
        cout << '\t' << *itr; 
    } 
    cout << endl; 
  
    // remove all elements up to 30 in gquiz2 
    cout << "\ngquiz2 after removal of elements less than 30 : "; 
    gquiz2.erase(gquiz2.begin(), gquiz2.find(30)); 
    for (itr = gquiz2.begin(); itr != gquiz2.end(); ++itr) 
    { 
        cout << '\t' << *itr; 
    } 
  
    // remove element with value 50 in gquiz2 
    int num; 
    num = gquiz2.erase (50); 
    cout << "\ngquiz2.erase(50) : "; 
    cout << num << " removed \t" ; 
    for (itr = gquiz2.begin(); itr != gquiz2.end(); ++itr) 
    { 
        cout << '\t' << *itr; 
    } 
  
    cout << endl; 
  
    //lower bound and upper bound for set gquiz1 
    cout << "gquiz1.lower_bound(40) : "
         << *gquiz1.lower_bound(40) << endl; 
    cout << "gquiz1.upper_bound(40) : "
         << *gquiz1.upper_bound(40) << endl; 
  
    //lower bound and upper bound for set gquiz2 
    cout << "gquiz2.lower_bound(40) : "
         << *gquiz2.lower_bound(40) << endl; 
    cout << "gquiz2.upper_bound(40) : "
         << *gquiz2.upper_bound(40) << endl; 
  
    return 0; 
  
} 

#include <set>

set<type> name;  //set<int> s;

// 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;
}