pop_heap(_RAIter, _RAIter, _Compare)：最近在分析别人代码的时候，不懂pop_heap, pop_back, push_heap：在此记录一下自己的学习所得，欢迎各位大神点评：

#include <vector>
#include <iostream>
#include <stdio.h>
#include <algorithm>
using namespace std;
class Index
{
    public:
        Index(int a, float b)
        {
            i = a;
            cost = b;
        }
        int i;
        float cost;
};
struct greater1
{
        bool operator()(const Index& a, const Index& b) const // operator() 调用操作符（）
        {                                                    // 当调用操作符的时候，相当于调用函数，（这处没有函数名）
            printf("操作符 a cost = %lf ,b cost = %lf\n", a.cost, b.cost);
            return a.cost > b.cost;// a>b是大最小堆 ：：a<b 是最大堆
        }
};
void print(vector<Index> sum);
void print1(vector<int> sum);
int main(int argc, char *argv[])
{

    vector<Index> a1;
    Index index(0,0);

//    for(int i=0; i<10; i++)
//    {
//        index.cost = (i)*100+1;
//        index.i = i;
//        a1.push_back(index);
//    }
    index.i = 0; index.cost = 1;
    a1.push_back(index);
    index.i = 1; index.cost = 101;
    a1.push_back(index);
    index.i = 2; index.cost = 201;
    a1.push_back(index);

    print(a1);
    pop_heap(a1.begin(), a1.end(), greater1());//当函数中第一个值小于最后一个值就行交换
    printf("进行pop heap 之后 ");
    print(a1);
    a1.pop_back();//删除最后一个值
    printf("进行pop back 之后 将最后一个值删除");
    print(a1);
    index.i = 11;
    index.cost = 2;//插入一个新值
    a1.push_back(index);
    printf("插入一个新值之后");
    print(a1);
    push_heap(a1.begin(), a1.end(), greater1());
    //push_heap 会根据所构造是什么堆，来将新插入的值放到什么位置
    printf("进行push heap之后 将最后一个值删除");
    print(a1);
    return 0;
}

引用：感谢下面博主

http://www.cplusplus.com/reference/algorithm/push_heap/

https://blog.csdn.net/l_tudou/article/details/51504477

https://www.1024do.com/?p=3378

https://blog.csdn.net/l_tudou/article/details/51504477

https://www.cnblogs.com/Baron-Lu/p/6677042.html