std::vector<int> myvector;

// set some values:

for (int i=1; i<10; i++) myvector.push_back(i); // 1 2 3 4 5 6 7 8 9

cout << "initial sequences: ";

for (std::vector<int>::iterator it=myvector.begin(); it!=myvector.end(); ++it)

std::cout << ' ' << *it;

std::cout << '\n';

std::random_shuffle (myvector.begin(), myvector.end());

cout << "random sequences: ";

for (std::vector<int>::iterator it=myvector.begin(); it!=myvector.end(); ++it)

std::cout << ' ' << *it;

std::cout << '\n';

// using default comparison (operator <):

//从输出看可以看出，此函数的作用就是快排的一部分

//选取一个数，然后分成两部分，左边的小，右边的大

cout << "nth_element: " << *(myvector.begin()+5) << endl;

std::nth_element (myvector.begin(), myvector.begin()+5, myvector.end());

// using function as comp

std::nth_element (myvector.begin(), myvector.begin()+5, myvector.end(),myfunction);

// print out content:

cout << "final sequences: ";

for (std::vector<int>::iterator it=myvector.begin(); it!=myvector.end(); ++it)

std::cout << ' ' << *it;

std::cout << '\n';

return 0;