The C++ Standard Library consists of the header, <algorithm> which defines a collection of functions (principally designed to deal with a range of elements). upper_bound() is a method in the STL that returns an iterator pointing to the first element in the range which compares greater than a certain value. The method returns the last iterator if no element compares greater than the value.
Syntax:
upper_bound( iterator_begin, iterator_end, val );
Parameters: The upper_bound() method accepts 3 parameters
- iterator_begin: Iterator to the initial position
- iterator_end: Iterator to the final position ( Note: the range is [iterator_begin,iterator_end) )
- val: Value of the upper bound to search for in the range
Return value: An iterator to the upper bound of val in the range. iterator_end if no elements compare more than val
Example of upper_bound() method
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int main()
{
vector<int> v;
v.push_back(1);
v.push_back(2);
v.push_back(5);
v.push_back(5);
v.push_back(5);
v.push_back(5);
v.push_back(6);
vector<int>::iterator it = upper_bound(v.begin(), v.end(), 5);
cout<<"Upper bound of element 5 is: "<< distance(v.begin(), it) << endl;
}
Output:
Upper bound of element 5 is: 6
