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迭代时删除[重复]

stl c++

nacho4d · 技术社区 · 15 年前

可能的重复:
Vector.erase(Iterator) causes bad memory access
iterate vector, remove certain items as I go.

你好, 我写了这篇文章,但我在运行时遇到了一些错误

for (vector< vector<Point> >::iterator track = tracks_.begin(); track != tracks_.end(); track++) {
        if (track->empty()) { // if track is empty, remove it
            tracks_.erase(track);
            track++; // is this ok?
        }else {   //if there are points, deque
            track->erase(track->begin()); //my program crashes here after a while... ;(
        }
    }

我有一个点向量(2个点),我称之为轨迹(1个轨迹是1个点向量) 我要检查每个轨迹,如果它们包含点,则删除第一个轨迹,否则删除该轨迹。是这样吗?

2 回复 | 直到 9 年前

sth 12 年前

erase() 使现有的迭代器失效,但是 returns 一个新的迭代器,指向删除的元素之后的元素。这个返回的迭代器可用于继续在向量上迭代。

vector< vector<Point> >::iterator track = tracks_.begin();
while (track != tracks_.end()) {
    if (track->empty()) {
        // if track is empty, remove it
        track = tracks_.erase(track);
    }
    else {
        //if there are points, deque
        track->erase(track->begin());
        ++track;
    }
}