Standard C++ Library Class Reference

in the range[first, i), pred(*j) == true, and, for any iterator k in the range [i, last), pred(*j) ==

false.

Note that partition does not necessarily maintain the relative order of the elements that match

and elements that do not match the predicate. Use the algorithm stable_partition if relative

order is important.

Complexity

The partition algorithm does at most (last - first)/2 swaps, and applies the predicate exactly last

- first times.

Example

// prtition.cpp

#include <functional>

#include <deque>

#include <algorithm>

#include <iostream.h>

// Create a new predicate from unary_function.

template<class Arg>

class is_even : public unary_function<Arg, bool>

{

public:

bool operator()(const Arg& arg1) { return (arg1 % 2) == 0; }

};

int main ()

{

// Initialize a deque with an array of integers.

int init[10] = { 1,2,3,4,5,6,7,8,9,10 };

deque<int> d1(init+0, init+10);

deque<int> d2(init+0, init+10);

// Print out the original values.

cout << "Unpartitioned values: " << "\t\t";

copy(d1.begin(), d1.end(), ostream_iterator<int>(cout," "));

cout << endl;