Description : This method returns an iterator pointing to the first element in the container which is greater or equal to the passed parameter 'x'.
Example :
//Run Code To Demonstrate use of set.lower_bound(x)
#include<iostream>
#include<set>
int main(){
// Create a set object holding integers
std::set<int> mySet {1,2,4,-5,6};
std::cout << "The lower_bound of 4 is: " << *(mySet.lower_bound(4)) << std::endl;
std::cout << "The lower_bound of 5 is: " << *(mySet.lower_bound(5)) << std::endl;
return 0;
}