std::sort的用法

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//
//alg_std::sort.cpp
//
#include <vector>
#include <algorithm>
#include <functional>      // For greater<int>( )
#include <iostream>
using namespace std;

// Return whether first element is greater than the second
bool UDgreater ( int elem1, int elem2 )
{
    return elem1 > elem2;
}

class Csort
{
public:

// Return whether first element is less than the second
    bool operator () (int a,int b) const
    {
        return a<b;
    };
};


int main( )
{
    vector <int> v1;
    vector <int>::iterator Iter1;
    int arr[12];
    int i;
    for ( i = 0 ; i <= 5 ; i++ )
    {
        v1.push_back( 2 * i );
        arr[i]=2*i;
    }
    for ( i = 6 ; i <= 11 ; i++ )
    {
        arr[i]=23-2*i;
    }

    int ii;
    for ( ii = 0 ; ii <= 5 ; ii++ )
    {
        v1.push_back( 2 * ii + 1 );
    }

    cout << "Original vector v1 = ( " ;
    for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
        cout << *Iter1 << " ";
    cout << ")" << endl;
    cout << "Original array arr = ( " ;
    for ( int n=0;n<12;n++ )
        cout << arr[n] << " ";
    cout << ")" << endl;

    //std::sort 默认排序方式
    sort( v1.begin( ), v1.end( ) );
    cout << "Sorted vector v1 = ( " ;
    for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
        cout << *Iter1 << " ";
    cout << ")" << endl;

    //使用自定义函数给数组排序，第三个参数为函数指针UDgreater
    //第二个参数为数据最大地址的后一位指针&arr[12]；
    sort( &arr[0], &arr[12],UDgreater);

    cout << "Resorted (UDgreater) array arr = ( " ;
    for ( int n=0;n<12;n++ ) cout << arr[n] << " ";
    cout << ")" << endl;
    //使用自定义类的 重载operator() 函数给数组排序，第三个参数为【类名()】
    sort( &arr[0], &arr[12],Csort());

    cout << "Resorted (Csort()) arr = ( " ;
    for ( int n=0;n<12;n++ ) cout << arr[n] << " ";
    cout << ")" << endl;

    //使用<functional>库中 greater<int>( ) 给向量V1排序；
    sort( v1.begin( ), v1.end( ), greater<int>( ) );
    //sort( v1.begin( ), v1.end( ), Csort() );

    cout << "Resorted (greater) vector v1 = ( " ;
    for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
        cout << *Iter1 << " ";
    cout << ")" << endl;

    // A user-defined (UD) binary predicate can also be used
    //sort( v1.begin( ), v1.end( ), UDgreater );
    sort( v1.begin( ), v1.end( ),Csort());
    cout << "Resorted (UDgreater) vector v1 = ( " ;
    for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
        cout << *Iter1 << " ";
    cout << ")" << endl;

    getchar();
    return 0;
}