如何通过STL列表向后迭代? [英] How do you iterate backwards through an STL list?
问题描述
我在Windows和Mac之间编写一些跨平台代码。
I'm writing some cross-platform code between Windows and Mac.
如果list :: end()返回一个迭代器,元素在列表中,并且可以在遍历列表向前时检查,什么是向后遍历的最好方法?
If list::end() "returns an iterator that addresses the location succeeding the last element in a list" and can be checked when traversing a list forward, what is the best way to traverse backwards?
此代码适用于Mac但不适用于Windows '减少超过第一元素):
This code workson the Mac but not on Windows (can't decrement beyond first element):
list<DVFGfxObj*>::iterator iter = m_Objs.end();
for (iter--; iter!=m_Objs.end(); iter--)// By accident discovered that the iterator is circular ?
{
}
这适用于Windows:
this works on Windows:
list<DVFGfxObj*>::iterator iter = m_Objs.end();
do{
iter--;
} while (*iter != *m_Objs.begin());
还有另外一种向后遍历的方法可以在for循环中实现?
Is there another way to traverse backward that could be implemented in a for loop?
推荐答案
使用reverse_iterator而不是迭代器。
使用rbegin()& rend()而不是begin()&
Use reverse_iterator instead of iterator. Use rbegin() & rend() instead of begin() & end().
另一种可能性是,如果您喜欢使用 BOOST_FOREACH 宏是使用Boost 1.36.0中引入的BOOST_REVERSE_FOREACH宏。
Another possibility, if you like using the BOOST_FOREACH macro is to use the BOOST_REVERSE_FOREACH macro introduced in Boost 1.36.0.
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