C++迭代器做什麼？

Question

代碼：（？）

vector<weight *> &res; 
    vector<weight>::iterator it = lower_bound(w.begin(), w.end(), queryweight); 
    while(it != w.end()) { 
     weight *w = &(*it); 
     if(w->weight >= 60) break; 
     res.push_back(w); 
     it++; 
    } 

我覺得lower_bound做一個二進制搜索，所以最後，不C++代碼打算拿到重物想？它在哪裏開始和停止？在這種情況下，循環是什麼while？謝謝！

Answer 1

lower_bound返回比所述第三參數少不元素的最低迭代（即，在載體的位置） - 在這裏，queryweight。然後while循環遍歷剩餘的元素，並且直到它到達具有大於或等於60的wight的元素將它們添加到矢量res。我假設輸入矢量w被排序，否則這個函數沒有多大意義。

逐行：

// Declare a vector of pointers to 'weight' objects, called res. 
// (I assume here that the "&" in the original question was a mistake.) 
vector<weight *> res; 

// Find the iterator that points to the lowest element in vector 'w' 
// such that the element is >= queryweight. 
vector<weight>::iterator it = lower_bound(w.begin(), w.end(), queryweight); 

// From this element forwards until the end of vector 'w' 
while(it != w.end()) { 
    // Get a pointer to the element. 
    weight *w = &(*it); 
    // If the 'wight' property of this element is >= 60, stop. 
    if(w->wight >= 60) break; 
    // Push the element onto the 'res' vector. 
    res.push_back(w); 
    // Move to the next element. 
    it++; 
}