lower_bound/upper_bound example

http://www.cplusplus.com/reference/algorithm/upper_bound/
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Return iterator to lower bound

Returns an iterator pointing to the first element in the range [first,last) which does not compare less than val.

Return iterator to upper bound

Returns an iterator pointing to the first element in the range [first,last) which compares greater than val.

 1 // lower_bound/upper_bound example
 2 #include <iostream>     // std::cout
 3 #include <algorithm>    // std::lower_bound, std::upper_bound, std::sort
 4 #include <vector>       // std::vector
 5 
 6 int main () {
 7   int myints[] = {10,20,30,30,20,10,10,20};
 8   std::vector<int> v(myints,myints+8);           // 10 20 30 30 20 10 10 20
 9 
10   std::sort (v.begin(), v.end());                // 10 10 10 20 20 20 30 30
11 
12   std::vector<int>::iterator low,up;
13   low=std::lower_bound (v.begin(), v.end(), 20); //          ^
14   up= std::upper_bound (v.begin(), v.end(), 20); //                   ^
15 
16   std::cout << "lower_bound at position " << (low- v.begin()) << '
';
17   std::cout << "upper_bound at position " << (up - v.begin()) << '
';
18 
19   return 0;
20 }