A question regarding stl nth_element

[Paul McKenzie]

No matter how I choose the second argument passed to nth_element, the elements in vec are always sorted as,
0,1,2,3,4,5,6,7,8,9
What is the use of second argument here?Thanks.

http://www.cplusplus.com/reference/a...m/nth_element/

Regards,

Paul McKenzie