递减 std::vector::begin 是否未定义,即使它从未使用过? [英]Is decrementing std::vector::begin undefined, even if it is never used?
使用std :: vector.erase(begin(),end())或std :: vector.erase(begin(),begin())是否安全? [英]Is it safe to use std::vector.erase(begin(), end()) or std::vector.erase(begin(), begin())?
在std :: vector :: begin()之前减少std :: vector :: iterator [英]Decrementing std::vector::iterator before std::vector::begin()