#include <algorithm> // std::sort
int myints[] = {32,71,12,45,26,80,53,33};
// using default comparison (operator <):
std::sort (myvector.begin(), myvector.begin()+4); //(12 32 45 71)26 80 53 33
// fun returns some form of a<b
std::sort (myvector.begin()+4, myvector.end(), myfunction); // 12 32 45 71(26 33 53 80)