STL_Associative_container_set_1.cpp

/*
In a set, the value of an element also identifies it (the value is itself the key, of type T), and each value must be unique. The value of the elements in a set cannot be modified once in the container (the elements are always const), but they can be inserted or removed from the container.

Internally, the elements in a set are always sorted following a specific strict weak ordering criterion indicated by its internal comparison object (of type Compare).

set containers are generally slower than unordered_set containers to access individual elements by their key, but they allow the direct iteration on subsets based on their order.

Sets are typically implemented as binary search trees.

Member functions:
(constructor)	Construct set (public member function)
(destructor)	Set destructor (public member function)
operator=	Copy container content (public member function)

Iterators:
begin	Return iterator to beginning (public member function)
end	Return iterator to end (public member function)
rbegin	Return reverse iterator to reverse beginning (public member function)
rend	Return reverse iterator to reverse end (public member function)
cbegin	Return const_iterator to beginning (public member function)
cend	Return const_iterator to end (public member function)
crbegin	Return const_reverse_iterator to reverse beginning (public member function)
crend	Return const_reverse_iterator to reverse end (public member function)

Capacity:
empty	Test whether container is empty (public member function)
size	Return container size (public member function)
max_size	Return maximum size (public member function)

Modifiers:
insert	Insert element (public member function)
erase	Erase elements (public member function)
swap	Swap content (public member function)
clear	Clear content (public member function)
emplace	Construct and insert element (public member function)
emplace_hint	Construct and insert element with hint (public member function)

Observers:
key_comp	Return comparison object (public member function)
value_comp	Return comparison object (public member function)

Operations:
find	Get iterator to element (public member function)
count	Count elements with a specific value (public member function)
lower_bound	Return iterator to lower bound (public member function)
upper_bound	Return iterator to upper bound (public member function)
equal_range	Get range of equal elements (public member function)

Allocator:
get_allocator	Get allocator (public member function)

*/
// CPP program to demonstrate various functions of Set in C++ STL
#include <iostream>
#include <iterator>
#include <set>
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);

	// only one 50 will be added to the set
	s1.insert(50);
	s1.insert(10);

	// printing set s1
	set<int, greater<int> >::iterator itr;
	cout << "\nThe set s1 is : \n";
	for (itr = s1.begin(); itr != s1.end(); itr++) 
		cout << *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 : \n";
	for (itr = s2.begin(); itr != s2.end(); itr++) 
		cout << *itr << " ";
	cout << endl;

	// remove all elements up to 30 in s2
	cout << "\ns2 after removal of elements less than 30 :\n";
	s2.erase(s2.begin(), s2.find(30));
	for (itr = s2.begin(); itr != s2.end(); itr++) 
		cout << *itr << " ";
	

	// remove element with value 50 in s2
	int num;
	num = s2.erase(50);
	cout << "\ns2.erase(50) : " << num << "elements removed\n";
	for (itr = s2.begin(); itr != s2.end(); itr++) 
		cout << *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;
}