typedef map<string,int> MapFileList;
int main()
{
MapFileList m_SingleList;
m_SingleList.insert(MapFileList::value_type("ttt", 0));
m_SingleList.insert(MapFileList::value_type("ddd", 1));
m_SingleList.insert(MapFileList::value_type("kkk", 0));
if (m_SingleList.size()>0)//是否保存了文件
{
MapFileList::iterator tIter;
int flag = 0;
/*该写法是错误的,陷入了循环中
for(tIter = m_SingleList.begin(); tIter != m_SingleList.end(); tIter++)
{
cout<<tIter->first<<" -- "<<tIter->second<<endl;
flag = tIter->second;
if(flag> 0 )
{
cout<<"erase "<<endl;
m_SingleList.erase(tIter);
}
}
*/ for(tIter = m_SingleList.begin(); tIter != m_SingleList.end();)
{
flag = tIter->second;
if (flag>0)
m_SingleList.erase(tIter++);
else
{
(*tIter).second = 1;
++tIter;
}
}
/* 这个写法也可以通过的
for(tIter = m_SingleList.begin(); tIter != m_SingleList.end();)
{
flag = tIter->second;
if (flag>0)
tIter = m_SingleList.erase(tIter);
else
{
(*tIter).second = 1;
++tIter;
}
}*/ }
}
分析:
在std::list中删除一个元素非常简单,直接使用erase方法即可,代码如下:
for(iter = list.begin(); iter != list.end();) {
if (shouldDelete(*iter))
iter = list.erase(iter);
else
++iter;
}
或者更简单点
list.erase(std::remove_if(list.begin(), list.end(), shouldDelete), list_end());
然而根据STL std::map中的定义void erase(iterator pos),此erase并不返回下一个元素的迭代器,因此不能采用std::list的方法
for(iter = map.begin(); iter != map.end();) {
if (shouldDelete(*iter))
map.erase(iter++);
else
++iter;
}
当然此方法同样也适合于std::list等