vector中如何显式调用const_reference和reference函数?
比如说我用vector<T>.at(num),希望得到对象的引用以便对其修改时,编译出错:c2440:cannot convert from 'const T' to 'T &'。因为vector的at、operator[]函数都有两套:const_reference at(size_type _Pos) const // subscript nonmutable sequence with checking;reference at(size_type _Pos) // subscript mutable sequence with checking——在隐式写法上无法区分,求STL的高人指点指点如何显示调用reference的!!在线等,急~