按照struct中指定字段排序

#include "stdafx.h"
#include 
#include 
using namespace std;

struct SPxSampleItem
{
    int nIndex; 
    int nValue; 

    SPxSampleItem()
    {
        Flush();
    }

    ~SPxSampleItem()
    {
        Flush();
    }

    void Flush()
    {
        nIndex = -1;
        nValue = -1;
    }
};

// 升序排序规则
inline bool index_ascending(const SPxSampleItem & m1, const SPxSampleItem & m2) 
{
    return m1.nIndex < m2.nIndex;
}

// 降序排序规则
inline bool value_descending(const SPxSampleItem & m1, const SPxSampleItem & m2) 
{
    return m1.nValue > m2.nValue;
}


int main( void)
{
    vector  vsItem;
    SPxSampleItem sSampleItem;
    sSampleItem.nIndex = 3;
    sSampleItem.nValue = 500;
    vsItem.push_back(sSampleItem);

    sSampleItem.nIndex = 2;
    sSampleItem.nValue = 5;
    vsItem.push_back(sSampleItem);

    sSampleItem.nIndex = 1;
    sSampleItem.nValue = 5000;
    vsItem.push_back(sSampleItem);

    sSampleItem.nIndex = 4;
    sSampleItem.nValue = 50;
    vsItem.push_back(sSampleItem);

    printf("\n The original data ...\n");
    vector  ::iterator iter = vsItem.begin();
    for(; iter != vsItem.end(); ++iter)
    {
        printf("Index: %4d, Value: %4d\n", iter->nIndex, iter->nValue);
    }

    // 根据value按降序排列
    ::sort(vsItem.begin(), vsItem.end(), value_descending);

    printf("\nAfter descending by value ...\n");
    iter = vsItem.begin();
    for(; iter != vsItem.end(); ++iter)
    {
        printf("Index: %4d, Value: %4d\n", iter->nIndex, iter->nValue);
    }

    // 根据index进行升序排列
    ::sort(vsItem.begin(), vsItem.end(), index_ascending);
    printf("\nAfter ascending by index ...\n");
    iter = vsItem.begin();
    for(; iter != vsItem.end(); ++iter)
    {
        printf("Index: %4d, Value: %4d\n", iter->nIndex, iter->nValue);
    }

    getchar();

    return 0;
}

运行结果:

结果