Use equal_range to locate the first and last point at which 5 can be inserted in order : equal_range « STL Algorithms Binary search « C++ Tutorial

1. C++ Tutorial
2. STL Algorithms Binary search
3. equal_range

#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

int main()
{
   const int SIZE = 10;
   int a1[] = { 2, 2, 4, 4, 4, 6, 6, 6, 6, 8 };
   vector< int > v( a1, a1 + SIZE );

   pair< vector< int >::iterator, vector< int >::iterator > eq;

   cout << "\n\nUse equal_range to locate the first and last point at which 5 can be inserted in order";
   eq = equal_range( v.begin(), v.end(), 5 );
   cout << "\n   Lower bound of 5 is element "
        << ( eq.first - v.begin() ) << " of vector v";
   cout << "\n   Upper bound of 5 is element "
        << ( eq.second - v.begin() ) << " of vector v" 
        << endl;            
   return 0;
}