Iterator 的用法

    DataRecord *ptr = (DataRecord *)iter;
    

另外參考一下下面的範例程式, 這個程式告訴你你可以刪除 vector 裡面的成員, 刪除後 vector 物件會自動重新排過

// cl -GX testVectorErase.cpp

#include <iostream>
#include <vector>
using namespace std;

void main()
{
    vector<int> data;
    int i;
    for (i=0; i<10; i++)
    {
        data.push_back(i+1);
//        if (i%2 == 1) data.erase(&data[i-1]);  
         // cause illegal access error in memory
    }

    for (i=0; i<data.size(); i++)
        cout << "(" << i << "," << data[i] << ") ";
    cout << endl;
    
    data.erase(&data[0]);
//    data.erase(&data[9]);   
// cause illegal access error
// i.e. erase(&data[0]) would move all members ahead one
//      position virtually
    data.erase(&data[8]);

    for (i=0; i<data.size(); i++)
        cout << "(" << i << "," << data[i] << ") ";
    cout << endl;

    vector<int>::iterator iter;
    int sum=0;
    for (i=0; i<data.size(); i++)
        sum += data[i];
    cout << "using array index " << sum << endl;

    sum = 0;
    for (iter=data.begin(); iter<data.end(); iter++)
        sum += *iter;
    cout << "using iter " << sum << endl;
}
    

F:\>testVectorErase
(0,1) (1,2) (2,3) (3,4) (4,5) (5,6) (6,7) (7,8) (8,9) (9,10)
(0,2) (1,3) (2,4) (3,5) (4,6) (5,7) (6,8) (7,9)
using array index 44
using iter 44